During an otherwise normal low-risk pregnancy, travel can be planned most safely up to the 32nd week. Commercial flying in pressurized cabins does not pose a threat to the fetus. An aisle seat will allow frequent walks. Adequate fluids should be taken during the flight. Travelling to endemic areas of yellow fever (Africa or Latin America) or of Zika virus (Latin America) is not advisable; since Zika virus can be sexually transmitted, partner travel should also be discussed (see Chapter 32). Similarly, it is inadvisable to travel to areas of Africa or Asia where chloroquine-resistant falciparum malaria is a hazard, since complications of malaria are more common in pregnancy.
Ideally, all immunizations should precede pregnancy. Live virus products are contraindicated during pregnancy (measles, rubella, yellow fever, and smallpox). Inactivated polio vaccine should be given subcutaneously instead of the oral live-attenuated vaccine. The varicella vaccine should be given 1–3 months before becoming pregnant. It is not recommended in pregnancy. Vaccines against pneumococcal pneumonia, meningococcal meningitis, and hepatitis A can be used as indicated. Pregnant women who are considered to be at high risk for hepatitis B and who have not been previously vaccinated should be vaccinated during pregnancy. The HPV vaccine is not recommended for pregnant women. However, adverse outcomes have not been described when used during pregnancy. If a woman who has started the vaccine series is found to be pregnant, the remaining doses should be administered when she is no longer pregnant.
The CDC lists pregnant women as a high-risk group for influenza. Annual influenza vaccination is indicated in all women who are pregnant or will be pregnant during the “flu season.” It can be given in the first trimester. The CDC also recommends that every pregnant woman receive a dose of Tdap during each pregnancy irrespective of her prior vaccination history. The optimal timing for such Tdap administration is between 27 and 36 weeks of gestation, in order to maximize the antibody response of the pregnant woman against pertussis and the passive antibody transfer to the infant. For any woman who was not previously vaccinated with Tdap and for whom the vaccine was not given during her pregnancy, Tdap should be administered immediately postpartum. Further, any teenagers or adults not previously vaccinated who will have close contact with the infant should also receive it, ideally 2 weeks before exposure to the child. This vaccination strategy is referred to as “cocooning,” and its purpose is to protect the infant aged younger than 12 months who is at particularly high risk for lethal pertussis.
Hepatitis A vaccine contains formalin-inactivated virus and can be given in pregnancy when needed. Pooled immune globulin to prevent hepatitis A is safe and does not carry risk of HIV transmission. Chloroquine can be used for malaria prophylaxis in pregnancy, and proguanil is also safe.
Water should be purified by boiling, since iodine purification may provide more iodine than is safe during pregnancy.
Prophylactic antibiotics or bismuth subsalicylate should not be used during pregnancy to prevent diarrhea. Oral rehydration and treatment of bacterial diarrhea with erythromycin or ampicillin if necessary is preferred.
American College of Obstetricians and Gynecologists. ACOG Committee Opinion No. 741: Maternal immunization. Obstet Gynecol. 2018 Jun;131(6):e214–7.