The Centers for Disease Control and Prevention (CDC) recommends HIV testing for all pregnant women as a part of routine prenatal care. The test is usually performed in the first trimester of pregnancy with other routine laboratory tests. HIV testing is recommended because HIV-infected women who do not receive testing are more likely to transmit the infection to their children.

HIV testing may be offered to pregnant women on an "opt-in" or an "opt-out" basis. In the "opt-in" model, women are counseled on HIV testing and elect to receive the test by signing a consent form. In the "opt-out" model, the HIV test is automatically performed with other routine prenatal tests. If a woman does not want to be tested for HIV, she must specifically refuse the test and sign a form declining testing. The CDC recommends "opt-out" testing for all pregnant women because it improves disease detection and treatment and helps reduce transmission to children.

If a woman chooses to decline testing, she will not receive the test. However, she will continue to receive HIV counseling throughout the pregnancy so that she may be as informed as possible about the disease and its impact. She will be offered HIV testing at all stages of her pregnancy in case she changes her mind.

HIV testing begins with a screening test. The most common screening test is the rapid HIV antibody test which tests for HIV antibodies in blood, urine, or oral fluid. HIV antibodies are only produced if an individual is infected with the disease. Therefore, presence of the antibodies is indicative of an HIV infection. Sometimes, however, a person may be infected with HIV but the body has not produced enough antibodies to be detected by the test. If a woman has risk factors for HIV infection but tests negative on the initial screening test, she should be retested in 3 months to confirm that she does not have HIV. Another screening test that is more specific is the HIV antigen/antibody test. This is a newer blood test that can detect HIV infection quicker than the antibody test because it detects both virus particles and antibodies in the blood.

Any woman who has a positive HIV screening test must receive follow-up testing to confirm the diagnosis. The follow-up test can differentiate HIV-1 from HIV-2 and is a more specific antibody test. It may also detect the virus directly in the bloodstream.

The important factors for successful prevention of GBS-EOD using IAP and the universal screening approach are:

- Reach most pregnant women for antenatal screens

- Proper sample collection

- Using an appropriate procedure for detecting GBS

- Administering a correct IAP to GBS carriers

Most cases of GBS-EOD occur in term infants born to mothers who screened negative for GBS colonization and in preterm infants born to mothers who were not screened, though some false-negative results observed in the GBS screening tests can be due to the test limitations and to the acquisition of GBS between the time of screening and delivery. These data show that improvements in specimen collection and processing methods for detecting GBS are still necessary in some settings. False-negative screening test, along with failure to receive IAP in women delivering preterm with unknown GBS colonization status, and the administration of inappropriate IAP agents to penicillin-allergic women account for most missed opportunities for prevention of cases of GBS-EOD.

GBS-EOD infections presented in infants whose mothers had been screened as GBS culture-negative are particularly worrying, and may be caused by incorrect sample collection, delay in processing the samples, incorrect laboratory techniques, recent antibiotic use, or GBS colonization after the screening was carried out.

According to current recommendations by the WHO, US CDC and U.S. Department of Health and Human Services (DHHS), all individuals with HIV should begin ART. The recommendation is stronger under the following conditions:

- CD4 count below 350 cells/mm

- High viral load (>100,000 copies/ml)

- Progression of HIV to AIDS

- Development of HIV-related infections and illnesses

- Pregnancy

Women are encouraged to begin treatment as soon as they are diagnosed with HIV. If they are diagnosed prior to pregnancy, they should continue with ART during the pregnancy. If the diagnosis of HIV is made during the pregnancy, ART should be initiated immediately.

No current culture-based test is both accurate enough and fast enough to be recommended for detecting GBS once labour starts. Plating of swab samples requires time for the bacteria to grow, meaning that this is unsuitable as an intrapartum point-of-care test.

Alternative methods to detect GBS in clinical samples (as vaginorectal swabs) rapidly have been developed, such are the methods based on nucleic acid amplification tests, such as polymerase chain reaction (PCR) tests, and DNA hybridization probes. These tests can also be used to detect GBS directly from broth media, after the enrichment step, avoiding the subculture of the incubated enrichment broth to an appropriate agar plate.

Testing women for GBS colonization using vaginal or rectal swabs at 35–37 weeks of gestation and culturing them in enriched media is not as rapid as a PCR test that would check whether the pregnant woman is carrying GBS at delivery. And PCR tests, allow starting IAP on admission to the labour ward in those women in whom it is not known if they are GBS carriers or not. PCR testing for GBS carriage could, in the future, be sufficiently accurate to guide IAP. However, the PCR technology to detect GBS must be improved and simplified to make the method cost-effective and fully useful as point-of-care testing]] to be carried out in the labour ward (bedside testing). These tests still cannot replace antenatal culture for the accurate detection of GBS carriers.

The data presented is for comparative and illustrative purposes only, and may have been superseded by updated data.

The apprehension is not necessarily data driven and is a cautionary response to the lack of clinical studies in pregnant women. The indication is a trade-off between the adverse effects of the drug, the risks associated with intercurrent diseases and pregnancy complications, and the efficiency of the drug to prevent or ameliorate such risks. In some cases, the use of drugs in pregnancy carries benefits that outweigh the risks. For example, high fever is harmful for the fetus in the early months, thus the use of paracetamol (acetaminophen) is generally associated with lower risk than the fever itself. Similarly, diabetes mellitus during pregnancy may need intensive therapy with insulin to prevent complications to mother and baby. Pain management for the mother is another important area where an evaluation of the benefits and risks is needed. NSAIDs such as Ibuprofen and Naproxen are probably safe for use for a short period of time, 48–72 hours, once the mother has reached the second trimester. If taking aspirin for pain management the mother should never take a dose higher than 100 mg.

Amniocentesis and chorionic villus sampling are procedures conducted to assess the fetus. A sample of amniotic fluid is obtained by the insertion of a needle through the abdomen and into the uterus. Chorionic villus sampling is a similar procedure with a sample of tissue removed rather than fluid. These procedures are not associated with pregnancy loss during the second trimester but they are associated with miscarriages and birth defects in the first trimester. Miscarriage caused by invasive prenatal diagnosis (chorionic villus sampling (CVS) and amniocentesis) is rare (about 1%).

Obstetric ultrasonography can detect fetal abnormalities, detect multiple pregnancies, and improve gestational dating at 24 weeks. The resultant estimated gestational age and due date of the fetus are slightly more accurate than methods based on last menstrual period. Ultrasound is used to measure the nuchal fold in order to screen for Downs syndrome.

According to American Congress of Obstetricians and Gynecologists, the main methods to calculate gestational age are:

- Directly calculating the days since the beginning of the last menstrual period.

- Early obstetric ultrasound, comparing the size of an embryo or fetus to that of a reference group of pregnancies of known gestational age (such as calculated from last menstrual periods), and using the mean gestational age of other embryos or fetuses of the same size. If the gestational age as calculated from an early ultrasound is contradictory to the one calculated directly from the last menstrual period, it is still the one from the early ultrasound that is used for the rest of the pregnancy.

- In case of in vitro fertilization, calculating days since oocyte retrieval or co-incubation and adding 14 days.

U.S. Code of Federal Regulations requires that certain drugs and biological products must be labelled very specifically with respect to their effects on pregnant populations, including a definition of a "pregnancy category." These rules are enforced by the Food and Drug Administration (FDA). The FDA does not regulate labelling for all hazardous and non-hazardous substances and some potentially hazardous substances are not assigned a pregnancy category.

Australia’s categorisations system takes into account the birth defects, the effects around the birth or when the mother gives birth, and problems that will arise later in the child's life caused from the drug taken. The system places them into a category of their severity that the drug could cause to the infant when it crosses the placenta(Australian Government, 2014).

A review article in The New England Journal of Medicine based on a consensus meeting of the Society of Radiologists in Ultrasound in America (SRU) has suggested that miscarriage should be diagnosed only if any of the following criteria are met upon ultrasonography visualization:

Blood is generally drawn from the father to help determine fetal antigen status. If he is homozygous for the antigen, there is a 100% chance of all offspring in the pairing to be positive for the antigen and at risk for HDN. If he is heterozygous, there is a 50% chance of offspring to be positive for the antigen. This test can help with knowledge for the current baby, as well as aid in the decision about future pregnancies. With RhD, the test is called the RhD genotype. With RhCE, and Kell antigen it is called an antigen phenotype.

In some cases, the direct coombs will be negative but severe, even fatal HDN can occur. An indirect coombs needs to be run in cases of anti-C, anti-c, and anti-M. Anti-M also recommends antigen testing to rule out the presence of HDN.

- Hgb - the infant’s hemoglobin should be tested from cord blood.

- Reticulocyte count - Reticulocytes are elevated when the infant is producing more blood to combat anemia. A rise in the retic count can mean that an infant may not need additional transfusions. Low retic is observed in infants treated with IUT and in those with HDN from anti-Kell

- Neutrophils - as Neutropenia is one of the complications of HDN, the neutrophil count should be checked.

- Thrombocytes - as thrombocytopenia is one of the complications of HDN, the thrombocyte count should be checked.

- Bilirubin should be tested from cord blood.

- Ferritin - because most infants affected by HDN have iron overload, a ferritin must be run before giving the infant any additional iron.

- Newborn Screening Tests - Transfusion with donor blood during pregnancy or shortly after birth can affect the results of the Newborn Screening Tests. It is recommended to wait and retest 10–12 months after last transfusion. In some cases, DNA testing from saliva can be used to rule out certain conditions.

Most Rh disease can be prevented by treating the mother during pregnancy or promptly (within 72 hours) after childbirth. The mother has an intramuscular injection of anti-Rh antibodies (Rho(D) immune globulin). This is done so that the fetal rhesus D positive erythrocytes are destroyed before the immune system of the mother can discover them and become sensitized. This is passive immunity and the effect of the immunity will wear off after about 4 to 6 weeks (or longer depending on injected dose) as the anti-Rh antibodies gradually decline to zero in the maternal blood.

It is part of modern antenatal care to give all rhesus D negative pregnant women an anti-RhD IgG immunoglobulin injection at about 28 weeks gestation (with or without a booster at 34 weeks gestation). This reduces the effect of the vast majority of sensitizing events which mostly occur after 28 weeks gestation. Giving Anti-D to all Rhesus negative pregnant women can mean giving it to mothers who do not need it (because her baby is Rhesus negative or their blood did not mix). Many countries routinely give Anti-D to Rhesus D negative women in pregnancy. In other countries, stocks of Anti-D can run short or even run out. Before Anti-D is made routine in these countries, stocks should be readily available so that it is available for women who need Anti-D in an emergency situation.

A recent review found research into giving Anti-D to all Rhesus D negative pregnant women is of low quality. However the research did suggest that the risk of the mother producing antibodies to attack Rhesus D positive fetal cells was lower in mothers who had the Anti-D in pregnancy. There were also fewer mothers with a positive kleihauer test (which shows if the mother’s and unborn baby’s blood has mixed).

Anti-RhD immunoglobulin is also given to non-sensitized rhesus negative women immediately (within 72 hours—the sooner the better) after potentially sensitizing events that occur earlier in pregnancy.

The discovery of cell-free DNA in the maternal plasma has allowed for the non-invasive determination of the fetal RHD genotype. In May 2017, the Society for Obstetrics and Gynecology of Canada is now recommending that the optimal management of the D-negative pregnant woman is based on the prediction of the fetal D-blood group by cell-free DNA in maternal plasma with targeted antenatal anti-D prophylaxis. This provides the optimal care for D-negative pregnant women and has been adopted as the standard approach in a growing number of countries around the world. It is no longer considered appropriate to treat all D-negative pregnant women with human plasma derivatives when there are no benefits to her or to the fetus in a substantial percentage of cases.

The pregnancy category of a medication is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. It does "not" include any risks conferred by pharmaceutical agents or their metabolites in breast milk.

Every drug has specific information listed in its product literature. The British National Formulary used to provide a table of drugs to be avoided or used with caution in pregnancy, and did so using a limited number of key phrases, but now Appendix 4 (which was the Pregnancy table) has been removed. Appendix 4 is now titled "Intravenous Additives". However, information that was previously available in the former Appendix 4 (pregnancy) and Appendix 5 (breast feeding) is now available in the individual drug monographs.

Opinions differ about optimal screening and diagnostic measures, in part due to differences in population risks, cost-effectiveness considerations, and lack of an evidence base to support large national screening programs. The most elaborate regimen entails a random blood glucose test during a booking visit, a screening glucose challenge test around 24–28 weeks' gestation, followed by an OGTT if the tests are outside normal limits. If there is a high suspicion, a woman may be tested earlier.

In the United States, most obstetricians prefer universal screening with a screening glucose challenge test. In the United Kingdom, obstetric units often rely on risk factors and a random blood glucose test. The American Diabetes Association and the Society of Obstetricians and Gynaecologists of Canada recommend routine screening unless the woman is low risk (this means the woman must be younger than 25 years and have a body mass index less than 27, with no personal, ethnic or family risk factors) The Canadian Diabetes Association and the American College of Obstetricians and Gynecologists recommend universal screening. The U.S. Preventive Services Task Force found there is insufficient evidence to recommend for or against routine screening.

Some pregnant women and careproviders choose to forgo routine screening due to the absence of risk factors, however this is not advised due to the large proportion of women who develop gestational diabetes despite having no risk factors present and the dangers to the mother and baby if gestational diabetes remains untreated.

When physical examination of the newborn shows signs of a vertically transmitted infection, the examiner may test blood, urine, and spinal fluid for evidence of the infections listed above. Diagnosis can be confirmed by culture of one of the specific pathogens or by increased levels of IgM against the pathogen.

Each type of vertically transmitted infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

Women with GDM may have high glucose levels in their urine (glucosuria). Although dipstick testing is widely practiced, it performs poorly, and discontinuing routine dipstick testing has not been shown to cause underdiagnosis where universal screening is performed. Increased glomerular filtration rates during pregnancy contribute to some 50% of women having glucose in their urine on dipstick tests at some point during their pregnancy. The sensitivity of glucosuria for GDM in the first 2 trimesters is only around 10% and the positive predictive value is around 20%.

Hormonal and other changes in pregnancy affect physical performance. In the first three months it is known that a woman’s body produces a natural surplus of red blood cells, which are well supplied with oxygen-carrying hemoglobin, in order to support the growing fetus. A study of athletes before and after pregnancy by Professor James Pivarnik at the Human Energy Research laboratory in Michigan State University has found there is a 60 per cent increase in blood volume and that this could improve the body’s ability to carry oxygen to muscles by up to 30 percent. This would have obvious positive effects on aerobic capacity. Other potential advantages are obtained from the surge in hormones that pregnancy induces, predominantly progesterone and estrogen, but also testosterone, which could increase muscle strength. Increases in hormones like relaxin, which loosens the hip joints to prepare for childbirth, may have a performance-enhancing effect on joint mobility.

Several world records have been set by female athletes shortly after giving birth to their first child. This is accepted as a natural and unintended event.

The effects of high blood pressure during pregnancy vary depending on the disorder and other factors. Preeclampsia does not in general increase a woman's risk for developing chronic hypertension or other heart-related problems. Women with normal blood pressure who develop preeclampsia after the 20th week of their first pregnancy, short-term complications--including increased blood pressure--usually go away within about 6 weeks after delivery.

Some women, however, may be more likely to develop high blood pressure or other heart disease later in life. More research is needed to determine the long-term health effects of hypertensive disorders in pregnancy and to develop better methods for identifying, diagnosing, and treating women at risk for these conditions.

Even though high blood pressure and related disorders during pregnancy can be serious, most women with high blood pressure and those who develop preeclampsia have successful pregnancies. Obtaining early and regular prenatal care is the most important thing you can do for you and your baby.

Blood pressure control can be accomplished before pregnancy. Medications can control blood pressure. Certain medications may not be ideal for blood pressure control during pregnancy such as angiotensin-converting enzyme (ACE) inhibitors and Angiotensin II (AII) receptor antagonists. Controlling weight gain during pregnancy can help reduce the risk of hypertension during pregnancy.

Types of HDN are classified by the type of antigens involved. The main types are ABO HDN, Rhesus HDN, Kell HDN, and other antibodies. ABO hemolytic disease of the newborn can range from mild to severe, but generally it is a mild disease. It can be caused by anti-A and anti-B antibodies. Rhesus D hemolytic disease of the newborn (often called Rh disease) is the most common form of severe HDN. Rhesus c hemolytic disease of the newborn can range from a mild to severe disease - is the third most common form of severe HDN. Rhesus e and rhesus C hemolytic disease of the newborn are rare. Combinations of antibodies, for example, anti-Rhc and anti-RhE occurring together can be especially severe.

Anti-Kell hemolytic disease of the newborn is most commonly caused by anti-K antibodies, the second most common form of severe HDN. Over half of the cases of anti-K related HDN are caused by multiple blood transfusions. Antibodies to the other Kell antigens are rare.

In some cases, the direct coombs will be negative but severe, even fatal HDN can occur. An indirect coombs needs to be run in cases of anti-C, anti-c, and anti-M. Anti-M also recommends antigen testing to rule out the presence of HDN.

There are divergent views as to whether everyone with an unprovoked episode of thrombosis should be investigated for thrombophilia. Even those with a form of thrombophilia may not necessarily be at risk of further thrombosis, while recurrent thrombosis is more likely in those who have had previous thrombosis even in those who have no detectable thrombophilic abnormalities. Recurrent thromboembolism, or thrombosis in unusual sites (e.g. the hepatic vein in Budd-Chiari syndrome), is a generally accepted indication for screening. It is more likely to be cost-effective in people with a strong personal or family history of thrombosis. In contrast, the combination of thrombophilia with other risk factors may provide an indication for preventative treatment, which is why thrombophilia testing may be performed even in those who would not meet the strict criteria for these tests. Searching for a coagulation abnormality is not normally undertaken in patients in whom thrombosis has an obvious trigger. For example, if the thrombosis is due to immobilization after recent orthopedic surgery, it is regarded as "provoked" by the immobilization and the surgery and it is less likely that investigations will yield clinically important results.

When venous thromboembolism occurs when a patient is experiencing transient major risk factors such as prolonged immobility, surgery, or trauma, testing for thrombophilia is not appropriate because the outcome of the test would not change a patient's indicated treatment. In 2013, the American Society of Hematology, as part of recommendations in the Choosing Wisely campaign, cautioned against overuse of thrombophilia screening; false positive results of testing would lead to people inappropriately being labeled as having thrombophilia, and being treated with anticoagulants without clinical need

In the United Kingdom, professional guidelines give specific indications for thrombophilia testing. It is recommended that testing be done only after appropriate counseling, and hence the investigations are usually not performed at the time when thrombosis is diagnosed but at a later time. In particular situations, such as retinal vein thrombosis, testing is discouraged altogether because thrombophilia is not regarded as a major risk factor. In other rare conditions generally linked with hypercoagulability, such as cerebral venous thrombosis and portal vein thrombosis, there is insufficient data to state for certain whether thrombophilia screening is helpful, and decisions on thrombophilia screening in these conditions are therefore not regarded as evidence-based. If cost-effectiveness (quality-adjusted life years in return for expenditure) is taken as a guide, it is generally unclear whether thrombophilia investigations justify the often high cost, unless the testing is restricted to selected situations.

Recurrent miscarriage is an indication for thrombophilia screening, particularly antiphospholipid antibodies (anti-cardiolipin IgG and IgM, as well as lupus anticoagulant), factor V Leiden and prothrombin mutation, activated protein C resistance and a general assessment of coagulation through an investigation known as thromboelastography.

Women who are planning to use oral contraceptives do not benefit from routine screening for thrombophilias, as the absolute risk of thrombotic events is low. If either the woman or a first-degree relative has suffered from thrombosis, the risk of developing thrombosis is increased. Screening this selected group may be beneficial, but even when negative may still indicate residual risk. Professional guidelines therefore suggest that alternative forms of contraception be used rather than relying on screening.

Thrombophilia screening in people with arterial thrombosis is generally regarded unrewarding and is generally discouraged, except possibly for unusually young patients (especially when precipitated by smoking or use of estrogen-containing hormonal contraceptives) and those in whom revascularization, such as coronary arterial bypass, fails because of rapid occlusion of the graft.

If a pregnant mother is identified as being infected with syphilis, treatment can effectively prevent congenital syphilis from developing in the fetus, especially if he or she is treated before the sixteenth week of pregnancy. The fetus is at greatest risk of contracting syphilis when the mother is in the early stages of infection, but the disease can be passed at any point during pregnancy, even during delivery (if the child had not already contracted it). A woman in the secondary stage of syphilis decreases her fetus's risk of developing congenital syphilis by 98% if she receives treatment before the last month of pregnancy. An afflicted child can be treated using antibiotics much like an adult; however, any developmental symptoms are likely to be permanent.

Kassowitz’s law is an empirical observation used in context of congenital syphilis stating that the greater the duration between the infection of the mother and conception, the better is the outcome for the infant. Features of a better outcome include less chance of stillbirth and of developing congenital syphilis.

The Centers for Disease Control and Prevention recommends treating symptomatic or babies born to infected mother with unknown treatment status with procaine penicillin G, 50,000 U/kg dose IM a day in a single dose for 10 days. Treatment for these babies can vary on a case by case basis. Treatment cannot reverse any deformities, brain, or permanent tissue damage that has already occurred.