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.

Pregnancy detection can be accomplished using one or more various pregnancy tests, which detect hormones generated by the newly formed placenta, serving as biomarkers of pregnancy. Blood and urine tests can detect pregnancy 12 days after implantation. Blood pregnancy tests are more sensitive than urine tests (giving fewer false negatives). Home pregnancy tests are urine tests, and normally detect a pregnancy 12 to 15 days after fertilization. A quantitative blood test can determine approximately the date the embryo was conceived because HCG doubles every 36 to 48 hours. A single test of progesterone levels can also help determine how likely a fetus will survive in those with a threatened miscarriage (bleeding in early pregnancy).

The management of PROM remains controversial, and depends largely on the gestational age of the fetus and other complicating factors. The risks of quick delivery (induction of labor) vs. watchful waiting in each case is carefully considered before deciding on a course of action.

As of 2012, the Royal College of Obstetricians and Gynaecologists advised, based on expert opinion and not clinical evidence, that attempted delivery during maternal instability, increases the rates of both fetal death and maternal death, unless the source of instability is an intrauterine infection.

In all women with PROM, the age of the fetus, its position in the uterus, and its wellbeing should be evaluated. This can be done with ultrasound, electronic fetal heart rate monitoring, and uterine activity monitoring. This will also show whether or not uterine contractions are happening which may be a sign that labor is starting. Signs and symptoms of infection should be closely monitored, and, if not already done, a group B streptococcus (GBS) culture should be collected.

At any age, if the fetal well-being appears to be compromised, or if intrauterine infection is suspected, the baby should be delivered quickly by artificially stimulating labor (induction of labor).

Doppler flow study is a type of ultrasound that measures the amount of blood flowing in and out of the placenta.

Regular movements of the baby is the best sign indicating that it is still in good health. The mother should keep a "kick-chart" to record the movements of her baby. A rate of fewer than 10 movements in 2 hours is not a good sign, and a doctor should be contacted. If there is a reduction in the number of movements it could indicate placental deterioration.

Before 34 weeks, the fetus is at a much higher risk of the complications of prematurity. Therefore, as long as the fetus is doing well, and there are no signs of infection or placental abruption, watchful waiting (expectant management) is recommended. The younger the fetus, the longer it takes for labor to start on its own, but most women will deliver within a week. Waiting usually requires a woman to stay in the hospital so that health care providers can watch her carefully for infection, placental abruption, umbilical cord compression, or any other fetal emergency that would require quick delivery by induction of labor.

In 2017, a review of watchful waiting vs the early birth strategy was conducted to ascertain which was associated with a lower overall risk. Focusing on the 24–37 week range, the review analysed 12 randomised controlled trials from the "Cochrane Pregnancy and Childbirth's Trials Register", concluding that "In women with PPROM before 37 weeks' gestation with no contraindications to continuing the pregnancy, a policy of expectant management with careful monitoring was associated with better outcomes for the mother and baby".There is believed to be a correlation between volume of amniotic fluid retained and neonatal outcomes before 26 weeks gestation. Amniotic fluid levels are an important consideration when debating expectant management vs clinical intervention, as low levels, or oligohydramnios, can result in lung and limb abnormalities. Additionally, labor and infection are less likely to occur when there are sufficient levels of amniotic fluid remaining in the uterus.

Obstetric ultrasound has become useful in the assessment of the cervix in women at risk for premature delivery. A short cervix preterm is undesirable: A cervical length of less than 25 mm at or before 24 weeks of gestational age is the most common definition of cervical incompetence.

Fetal fibronectin (fFN) has become an important biomarker—the presence of this glycoprotein in the cervical or vaginal secretions indicates that the border between the chorion and deciduas has been disrupted. A positive test indicates an increased risk of preterm birth, and a negative test has a high predictive value. It has been shown that only 1% of women in questionable cases of preterm labor delivered within the next week when the test was negative.

Miscarriage is the loss of a pregnancy prior to 20 weeks. In the UK miscarriage is defined as the loss of a pregnancy during the first 23 weeks.

Some disorders and conditions can mean that pregnancy is considered high-risk (about 6-8% of pregnancies in the USA) and in extreme cases may be contraindicated. High-risk pregnancies are the main focus of doctors specialising in maternal-fetal medicine.

Serious pre-existing disorders which can reduce a woman's physical ability to survive pregnancy include a range of congenital defects (that is, conditions with which the woman herself was born, for example, those of the heart or , some of which are listed above) and diseases acquired at any time during the woman's life.

If a small amount of bleeding is seen in early pregnancy a physician may request:

- A quantitative human chorionic gonadotropin (hCG) blood test to confirm the pregnancy or assist in diagnosing a potential miscarriage

- Transvaginal pelvic ultrasonography to confirm that the pregnancy is not outside of the uterus

- Blood type and Rh test to rule out hemolytic disease of the newborn

For bleeding seen in later pregnancy tests may include:

- Complete blood count (CBC) and blood type and screen

- Ultrasound to determine placental location

- Kleihauer-Betke (KB) test especially if there was maternal trauma

The following tests have been promoted as supposedly diagnosing placental insufficiency, but all have been unsuccessful at predicting stillbirth due to placental insufficiency:

- Placental grading

- Amniotic fluid index

- Fetal biophysical profile test scoring

- Doppler velocimetry

- Routine ultrasound scanning

- Detection and management of maternal diabetes mellitus

- Antenatal fetal heart rate monitoring using cardiotocography

- Vibroacoustic stimulation, fetal movement counting

- Home vs. hospital-based bed rest and monitoring in high-risk pregnancy

- In-hospital fetal surveillance unit

- Use of the partograph during labor

- Cardiotocography during labor with or without pulse oximetry

The Kleihauer–Betke test is a blood test used to measure the amount of foetal hemoglobin transferred from a foetus to its mother's bloodstream. It takes advantage of the differential resistance of foetal hemoglobin to acid. A standard blood smear is prepared from the mother's blood, and exposed to an acid bath. This removes adult hemoglobin, but not foetal hemoglobin, from the red blood cells. Subsequent staining, using Shepard's method, makes fetal cells (containing foetal hemoglobin) appear rose-pink in color, while adult red blood cells are only seen as "ghosts". 2000 cells are counted under the microscope and a percentage of foetal to maternal cells is calculated.

Foetal-maternal haemorrhage can also be diagnosed by flow cytometry, using anti-foetal hemoglobin antibodies (anti-HbF).

Chorioamnionitis can be diagnosed from a histologic examination of the fetal membranes.

Infiltration of the chorionic plate by neutrophils is diagnostic of (mild) chorioamnionitis. More severe chorioamnionitis involves subamniotic tissue and may have fetal membrane necrosis and/or abscess formation.

Severe chorioamnionitis may be accompanied by vasculitis of the umbilical blood vessels (due to the fetus' inflammatory cells) and, if very severe, funisitis (inflammation of the umbilical cord's connective tissue).

Pregnant patients may have bleeding from the reproductive tract due to trauma, including sexual trauma, neoplasm, most commonly cervical cancer, and hematologic disorders. Molar pregnancy (also called hydatiform mole) is a type of pregnancy where the sperm and the egg have joined within the uterus, but the result is a cyst resembling a grape-like cluster rather than an embryo. Bleeding can be an early sign of this tumor developing.

Chorioamnionitis is a risk factor for periventricular leukomalacia and cerebral palsy.

While most pregnant women experience some itch from time to time, itching on the palms and soles without a visible rash, or persisting severe or extensive itch symptoms should be reported to the midwife or obstetrican.

To obtain a diagnosis of ICP, there are two LFT (liver function tests) and Serum bile acid test. The liver function tests (LFTs) is a simple blood test, the results of which should be available by the next day. If the ALT level is elevated, this, plus pruritus of palms and soles, could be considered as potentially diagnostic of ICP but only with elevated bile acid levels (however LFTs are not always elevated in ICP patients). The serum bile acid blood test for ICP is a quantitative measurement of bile salts. The results of this test often take longer to return, but the test is more specific for ICP.

Other problems with the liver that occur in pregnancy should be considered by the treating clinician. These include preeclampsia, the HELLP syndrome, and acute fatty liver of pregnancy. Furthermore, other causes of hepatitis, like hepatitis viruses, cancer and certain medications, should also be considered.

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.

Depending on gestational age the differential diagnoses for abdominal pregnancy include miscarriage, intrauterine fetal death, placental abruption, an acute abdomen with an intrauterine pregnancy and a fibroid uterus with an intrauterine pregnancy .

Upon diagnosis, many providers will prescribe Ursodeoxycholic Acid. While there is no cure for ICP, and no way to guarantee a successful outcome, studies have shown a slightly better fetal and maternal outcome from administration of Ursodeoxycholic Acid, whereas Cholestyramine appears to only relieve itching.

If additional blood tests to check clotting function identify a problem, giving Vitamin K may help avoid the risk of hemorrhage at delivery.

Delivery by 35–37 completed weeks may be important to fetal outcome as a recent study demonstrated that in severe ICP (defined as bile acids greater than 40 umol/L) the risk of stillbirth was 1.5% compared to 0.5% of uncomplicated pregnancies. This risk rose further if bile acids doubled,

If ongoing and rapid haemorrhage is occurring then immediate delivery of the foetus may be indicated if the fetus is sufficiently developed. If the haemorrhage has already occurred and now stopped, an inutero transfusion of red cells to the foetus may be recommended.

Women should continue their ART regimen through childbirth. In addition to the three-drug regimen outlined above, intravenous (IV) zidovudine should be administered if the maternal viral load is >1,000 copies/mL or if it is unknown. This will help reduce the risk of HIV transmission during labor and delivery.

The viral load helps determine which mode of delivery is safest for the mother and the baby. In cases where the viral load is low (<1000 copies/mL), the risk of transmission is low and a vaginal delivery may be performed. A cesarean section, on the other hand, is generally performed at 38 weeks gestation under the following circumstances:

- Viral load is high (>1000 copies/mL) or unknown at the time of delivery

- Mother did not receive ART during the pregnancy

- Mother is concerned about exposing her child to infected blood and genital secretions during the delivery

If, before her scheduled cesarean section, a woman's water breaks and she goes into labor, a cesarean section may not significantly reduce the risk of infection transmission. Under this circumstance, if there is no other medical reason to proceed with a cesarean section, a vaginal delivery may be performed and may be the safest for the mother and the baby.

Women who present to the hospital in labor with an unknown HIV status should undergo immediate HIV testing. If the initial screening test is positive, the mother should immediately be started on IV zidovudine and the baby should receive prophylactic ART after birth. A confirmatory HIV test should also be performed in the meantime. If the test results are positive, treatment should continue with the antiretrovirals. If the results are negative, the medications may be stopped.

To diagnose the rare primary abdominal pregnancy, Studdiford's criteria need to be fulfilled: tubes and ovaries should be normal, there is no abnormal connection (fistula) between the uterus and the abdominal cavity, and the pregnancy is related solely to the peritoneal surface without signs that there was a tubal pregnancy first. Studdiford's criteria were refined in 1968 by Friedrich and Rankin to include microscopic findings.

Taking aspirin is associated with a 1% to 5% reduction in pre-eclampsia and a 1% to 5% reduction in premature births in women at high risk. The World Health Organization recommends low-dose aspirin for the prevention of pre-eclampsia in women at high risk and recommends it be started before 20 weeks of pregnancy. The United States Preventive Services Task Force recommends a low-dose regimen for women at high risk beginning in the 12th week. Benefits are less if started after 16 weeks.

When a baby is born bottom first there is more risk that the birth will not be straight forward and that the baby could be harmed. For example, when the baby's head passes through the mother’s pelvis the umbilical cord can be compressed which prevents delivery of oxygenated blood to the baby. Due to this and other risks, babies in breech position are usually born by a planned caesarean section in developed countries.

Caesarean section reduces the risk of harm or death for the baby but does increase risk of harm to the mother compared with a vaginal delivery. It is best if the baby is in a head down position so that they can be born vaginally with less risk of harm to both mother and baby. The next section is looking at External cephalic version or ECV which is a method that can help the baby turn from a breech position to a head down position.

Vaginal birth of a breech baby has its risks but caesarean sections are not always available or possible, a mother might arrive in hospital at a late stage of her labour or may choose not to have a caesarean section. In these cases, it is important that the clinical skills needed to deliver breech babies are not lost so that mothers and babies are as safe as possible. Compared with developed countries, planned caesarean sections have not produced as good results in developing countries - it is suggested that this is due to more breech vaginal deliveries being performed by experienced, skilled practitioners in these settings.