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.

In low-risk pregnancies, the association between cigarette smoking and a reduced risk of pre-eclampsia has been consistent and reproducible across epidemiologic studies. High-risk pregnancies (those with pregestational diabetes, chronic hypertension, history of pre-eclampsia in a previous pregnancy, or multifetal gestation) showed no significant protective effect. The reason for this discrepancy is not definitively known; research supports speculation that the underlying pathology increases the risk of preeclampsia to such a degree that any measurable reduction of risk due to smoking is masked. However, the damaging effects of smoking on overall health and pregnancy outcomes outweighs the benefits in decreasing the incidence of preeclampsia. It is recommended that smoking be stopped prior to, during and after pregnancy.

Studies suggest that marijuana use in the months prior to or during the early stages of pregnancy may interfere with normal placental development and consequently increase the risk of preeclampsia.

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.

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.

It is the goal of evolutionary medicine to find treatments for diseases that are informed by the evolutionary history of a disease. It has been suggested that gestational hypertension is linked to insulin resistance during pregnancy. Both the increase in blood sugar that can lead to gestational diabetes and the increase in blood pressure that can lead to gestational hypertension are mechanisms that mean to optimize the amount of nutrients that can be passed from maternal tissue to fetal tissue. It has been suggested that techniques used to combat insulin insensitivity might also prove beneficial to those suffering from gestational hypertension. Measures to avoid insulin resistance include avoiding obesity before pregnancy, minimizing weight gain during pregnancy, eating foods with low glycemic indexes, and exercising.

There is no specific treatment, but is monitored closely to rapidly identify pre-eclampsia and its life-threatening complications (HELLP syndrome and eclampsia).

Drug treatment options are limited, as many antihypertensives may negatively affect the fetus. Methyldopa, hydralazine, and labetalol are most commonly used for severe pregnancy hypertension.

The fetus is at increased risk for a variety of life-threatening conditions, including pulmonary hypoplasia (immature lungs). If the dangerous complications appear after the fetus has reached a point of viability, even though still immature, then an early delivery may be warranted to save the lives of both mother and baby. An appropriate plan for labor and delivery includes selection of a hospital with provisions for advanced life support of newborn babies.

Although the risk of placental abruption cannot be eliminated, it can be reduced. Avoiding tobacco, alcohol and cocaine during pregnancy decreases the risk. Staying away from activities which have a high risk of physical trauma is also important. Women who have high blood pressure or who have had a previous placental abruption and want to conceive must be closely supervised by a doctor.

The risk of placental abruption can be reduced by maintaining a good diet including taking folic acid, regular sleep patterns and correction of pregnancy-induced hypertension.

It is crucial for women to be made aware of the signs of placental abruption, such as vaginal bleeding, and that if they experience such symptoms they must get into contact with their health care provider/the hospital "without any delay".

The use of recreational drugs in pregnancy can cause various pregnancy complications.

- Ethanol during pregnancy can cause fetal alcohol syndrome and fetal alcohol spectrum disorder. Studies have shown that light to moderate drinking during pregnancy might not pose a risk to the fetus, although no amount of alcohol during pregnancy can be guaranteed to be absolutely safe.

- Tobacco smoking during pregnancy can cause a wide range of behavioral, neurological, and physical difficulties. Smoking during pregnancy causes twice the risk of premature rupture of membranes, placental abruption and placenta previa. Smoking is associated with 30% higher odds of preterm birth.

- Prenatal cocaine exposure is associated with premature birth, birth defects and attention deficit disorder.

- Prenatal methamphetamine exposure can cause premature birth and congenital abnormalities. Short-term neonatal outcomes show small deficits in infant neurobehavioral function and growth restriction. Long-term effects in terms of impaired brain development may also be caused by methamphetamine use.

- Cannabis in pregnancy has been shown to be teratogenic in large doses in animals, but has not shown any teratogenic effects in humans.

The four goals of the treatment of eclampsia are to stop and prevent further convulsions, to control the elevated blood pressure, to deliver the baby as promptly as possible, and to monitor closely for the onset of multi-organ failure.

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.

Treatment depends on the amount of blood loss and the status of the fetus. If the fetus is less than 36 weeks and neither mother or fetus is in any distress, then they may simply be monitored in hospital until a change in condition or fetal maturity whichever comes first.

Immediate delivery of the fetus may be indicated if the fetus is mature or if the fetus or mother is in distress. Blood volume replacement to maintain blood pressure and blood plasma replacement to maintain fibrinogen levels may be needed. Vaginal birth is usually preferred over Caesarean section unless there is fetal distress. Caesarean section is contraindicated in cases of disseminated intravascular coagulation. People should be monitored for 7 days for postpartum hemorrhage. Excessive bleeding from uterus may necessitate hysterectomy. The mother may be given Rhogam if she is Rh negative.

Detection and management of pre-eclampsia is critical to reduce the risk of eclampsia. The USPSTF recommends regular checking of blood pressure through pregnancy in order to detect preeclampsia. Appropriate management of women with pre-eclampsia generally involves the use of magnesium sulphate to prevent convulsions.

Intrauterine exposure to environmental toxins in pregnancy has the potential to cause adverse effects on the development of the embryo/fetus and to cause pregnancy complications. Air pollution has been associated with low birth weight infants. Conditions of particular severity in pregnancy include mercury poisoning and lead poisoning. To minimize exposure to environmental toxins, the "American College of Nurse-Midwives" recommends: checking whether the home has lead paint, washing all fresh fruits and vegetables thoroughly and buying organic produce, and avoiding cleaning products labeled "toxic" or any product with a warning on the label.

Pregnant women can also be exposed to toxins in the workplace, including airborne particles. The effects of wearing N95 filtering facepiece respirators are similar for pregnant women as non-pregnant women, and wearing a respirator for one hour does not affect the fetal heart rate.

Immunizations have not been found to cause miscarriage. There is no significant association between antidepressant medication exposure and spontaneous abortion. The risk of miscarriage is not likely decrease by discontinuing SSRI prior to pregnancy. Some available data suggest that there is a small increased risk of miscarriage for women taking any antidepressant, though this risk becomes less statistically significant when excluding studies of poor quality.

Medicines that increase the risk of miscarriage include:

- retinoids

- nonsteroidal anti-inflammatory drugs (NSAIDs) , such as ibuprofen

- misoprostol

- methotrexate

Levels of hemoglobin are lower in the third trimesters. According to the United Nations (UN) estimates, approximately half of pregnant women suffer from anemia worldwide. Anemia prevalences during pregnancy differed from 18% in developed countries to 75% in South Asia.

Treatment varies due to the severity of the anaemia, and can be used by increasing iron containing foods, oral iron tablets or by the use of parenteral iron.

Ionizing radiation levels given to a woman during cancer treatment cause miscarriage. Exposure can also impact fertility. The use of chemotherapeutic drugs used to treat childhood cancer increases the risk of miscarriage.

Being pregnant decreases the risk of relapse in multiple sclerosis; however, during the first months after delivery the risk increases. Overall, pregnancy does not seem to influence long-term disability. Multiple sclerosis does not increase the risk of congenital abnormality or miscarriage.

Women who have had premature rupture of membranes (PROM) are more likely to experience it in future pregnancies. There is not enough data to recommend a way to specifically prevent future PROM. However, any woman that has had a history of preterm delivery, because of PROM or not, is recommended to take progesterone supplementation to prevent preterm birth recurrence.

When the fetus is premature (< 37 weeks), the risk of being born prematurely must be weighed against the risk of prolonged membrane rupture. As long as the fetus is 34 weeks or greater, delivery is recommended as if the baby was term (see above).

Adoption of specific professional policies can immediately reduce risk of preterm birth as the experience in assisted reproduction has shown when the number of embryos during embryo transfer was limited.

Many countries have established specific programs to protect pregnant women from hazardous or night-shift work and to provide them with time for prenatal visits and paid pregnancy-leave. The EUROPOP study showed that preterm birth is not related to type of employment, but to prolonged work (over 42 hours per week) or prolonged standing (over 6 hours per day). Also, night work has been linked to preterm birth. Health policies that take these findings into account can be expected to reduce the rate of preterm birth.

Preconceptional intake of folic acid is recommended to reduce birth defects. There is significant evidence that long-term (> one year) use of folic acid supplement preconceptionally may reduce premature birth. Reducing smoking is expected to benefit pregnant women and their offspring.

Pregnancy does not have an adverse effect on the course of Behçet's disease and may possibly ameliorate its course. Still, there is a substantial variability in clinical course between patients and even for different pregnancies in the same patient. Also, the other way around, Behçet's disease confers an increased risk of pregnancy complications, miscarriage and Cesarean section.

Healthy eating can be instituted at any stage of the pregnancy including nutritional adjustments, use of vitamin supplements, and smoking cessation. Calcium supplementation in women who have low dietary calcium reduces the number of negative outcomes including preterm birth, pre-eclampsia, and maternal death. The World Health Organization (WHO) suggests 1.5-2 g of calcium supplements daily, for pregnant women who have low levels calcium in their diet. Supplemental intake of C and E vitamins have not been found to reduce preterm birth rates. Different strategies are used in the administration of prenatal care, and future studies need to determine if the focus can be on screening for high-risk women, or widened support for low-risk women, or to what degree these approaches can be merged. While periodontal infection has been linked with preterm birth, randomized trials have not shown that periodontal care during pregnancy reduces preterm birth rates.

Bed rest has not been found to improve outcomes and therefore is not typically recommended.

Mothers whose fetus is diagnosed with intrauterine growth restriction by ultrasound can use management strategies based on monitoring and delivery methods. One of these monitoring techniques is an umbilical artery Doppler. This method has been shown to decrease risk of morbidity and mortality before and after parturition among IUGR patients.

Time of delivery is also a management strategy and is based on parameters collected from the umbilical artery doppler. Some of these include: pulsatility index, resistance index, and end-diastolic velocities, which are measurements of the fetal circulation.

With treatment, maternal mortality is about 1 percent, although complications such as placental abruption, acute renal failure, subcapsular liver hematoma, permanent liver damage, and retinal detachment occur in about 25% of women. Perinatal mortality (stillbirths plus death in infancy) is between 73 and 119 per 1000 babies of woman with HELLP, while up to 40% are small for gestational age. In general, however, factors such as gestational age are more important than the severity of HELLP in determining the outcome in the baby.

Low birthweight, pre-term birth and pre-eclampsia have been associated with maternal periodontitis exposure. But the strength of the observed associations is inconsistent and vary according to the population studied, the means of periodontal assessment and the periodontal disease classification employed. However the best is that the risk of low birth weight can be reduced with very simple therapy. Treatment of periodontal disease during gestation period is safe and reduction in inflammatory burden reduces the risk of preterm birth as well as low birth weight.