Immunization in pregnancy
Ideally, preconceptional administration of vaccines to prevent fetal and maternal disease is a better strategy than immunization during pregnancy. There is no evidence that vaccinating pregnant women with an inactivated virus, bacterial vaccines, or toxoids poses a risk.
However, live vaccines pose a theoretical risk to the fetus of transmission of the organism.When administering a live or live attenuated vaccine to a pregnant woman, the risk of exposure to disease and its adverse effects must be balanced against the efficacy of the vaccine. The obstetric care provider should counsel the pregnant woman about the risks and benefits of vaccine as well as potential exposure to the disease.
Starting at the first prenatal visit, attention should be paid to the immunization history of each pregnant woman. Women who have inadvertently received immunization with a live or live attenuated vaccine during pregnancy should not be advised to terminate the pregnancy because of the teratogenicity. Non-pregnant women immunized with a live or a live attenuated vaccine should be counselled to delay pregnancy for at least 4 weeks. Pregnant women should be offered the influenza vaccine during the influenza season. Neither inactivated nor live attenuated vaccine administered to lactating women affect the safety of breastfeeding for mothers or infants. Breastfeeding is not a contraindication for any vaccine except smallpox vaccine.
Tables 17.1 and 17.2 summarize the vaccines used for active and passive immunization during pregnancy.
Table 17.1 Active immunization during pregnancy
| Vaccine | Virus | Maternal risk from disease | Fetal risk from disease | Fetal risk from vaccine | Immunization in pregnancy | Dose schedule | Comment |
| Measles | Live attenuated | High morbidity, low mortality | High miscarriage rate, may cause malformations | None confirmed | Contraindicated | Single dose SC | Performed postpartum |
| Mumps | Live attenuated | Low morbidity, low mortality | Possible high miscarriage rate | None confirmed | Contraindicated | Single dose SC | Performed postpartum |
| Rubella | Live attenuated | Low morbidity, low mortality | High miscarriage rate, congenital rubella syndrome | None confirmed | Contraindicated | Single dose SC | Performed postpartum Theoretic teratogenicity not confirmed |
| Poliomyelitis | Live attenuated | High morbidity | Anoxic fetal damage reported | None confirmed | Not routinely recommended in USA, except women at increased risk of exposure | Two doses SC at 4-8 weeks interval and third dose 6-12 months from second dose | Indicated for susceptible pregnant women travelling in endemic areas |
| Yellow fever | Live attenuated | High morbidity, high mortality | Unknown | Unknown | Contraindicated | Single dose SC | |
| Varicella | Live attenuated | Possible increase in severe pneumonia | Congenital varicella 2% if infected during second trimester | None confirmed | Contraindicated | Two doses needed 4-8 weeks apart | Performed postpartum |
| Influenza | Inactivated | Increase in morbidity and mortality during epidemic of new antigenic strain | Possible increased miscarriage rate | None confirmed | Any time | Single dose IM | |
| Rabies | Killed | 100% fatality | Determined by maternal disease | Unknown | Indication for prophylaxis considered individually | Public health authorities consulted for indications, dosage and route | |
| Hepatitis B | Purified surface antigen | Possible increased severity in third trimester | Possible increased miscarriage rate and preterm birth | None reported | Pre exposure and post exposure for women at risk of infection | Three-doses series IM at 0, 1, and 6 months | Used with hepatitis B immunoglobulin for some exposure |
| Hepatitis A | Inactivated | No increased risk during pregnancy | None reported | Pre exposure and post exposure for women at risk of infection | Two doses 6 month apart | ||
| Pneumococcus | Polyvalent polysaccharide | No increased risk | Unknown, but depends on maternal illness | None reported | Recommended in case of asplenia; metabolic, renal, cardiac, pulmonary diseases; smokers; immunosuppressed, | Single dose SC or IM | Consider repeat dose in 6 years in high risk women |
| Meningococcus | Quadrivalent polysaccharide | High morbidity, high mortality | Unknown, but depends on maternal illness | None reported | Recommended in unusual outbreak situations | Single dose SC | Public health authorities consulted |
| Typhoid | Killed or live attenuated | High morbidity | Unknown | None confirmed | Recommended for close, continued exposure or travel in endemic areas | Killed: Primary: two injection SC, Booster: single dose SC | Oral vaccine preferred |
| Anthrax | Preparation from cell-free filtrate of B anthracis | High morbidity, high mortality | Unknown, but depends on maternal illness | None confirmed | Not routinely recommended | Six-dose primary vaccination SC, then annual booster | Teratogenicity of vaccine theoretical |
| Tetanus/ diphtheria | Combined toxoids | Tetanus mortality 30%, diphtheria mortality 10% | Neonatal tetanus mortality 60% | None confirmed | Lack of primary series or no booster within past 10 years | Updating immune status during antepartum care |
SC, subcutaneously; IM, intramuscularly.
Reproduced from Sabaratnam Arulkumaran, Lesley Regan, Aris Papageorghiou, Ash Monga, and David Farquharson, (Chapter 8) in Oxford Desk Reference Obstetrics and Gynaecology, Oxford University Press, pp, 259-260 with permission from Oxford University Press,
Table 17.2 Passive immunization during pregnancy
| Vaccine | Virus | Maternal risk from disease | Fetal/neonatal risk from disease | Fatal risk from vaccine | Immunization in pregnancy | Dose schedule | Comment |
| Hepatitis B | Hepatitis B immune globulin | Possible increased severity in third trimester | Possible increase in miscarriage and preterm birth, neonatal hepatitis may occur | None reported | Postexposure prophylaxis | Consult Practice Advisory Committee recommendation | Usually given with hepatitis B vaccine |
| Rabies | Rabies immune globulin | 100% fatality | Determined by maternal disease | None reported | Postexposure prophylaxis | Half dose at injury site and half in deltoid | Used in conjunction with rabies killed virus vaccine |
| Tetanus | Tetanus immune globulin | High morbidity, mortality 60% | Neonatal tetanus with 60% mortality | None reported | Postexposure prophylaxis | Single dose IM | Used in conjunction with tetanus toxoid |
| Varicella | Varicella zoster immune globulin | Possible increase in severe varicella pneumonia | Can cause congenital varicella with increased mortality in neonatal period | None reported | Considered for healthy pregnant women exposed to varicella to protect against maternal, not congenital infection | Single dose IM within 96 hours of exposure | Indicated in newborn of women who developed varicella within 4 days before delivery or 2 days following delivery, not indicated for prevention of congenital varicella |
| Hepatitis A | Standard immune globulin | Possible increased severity during third trimester | Possible increase in miscarriage and preterm birth, | None reported | Post exposure prophylaxis, but the vaccine should be used with immune globulin | Single dose IM | Immune globulin should be given as soon as possible and within 2 weeks of exposure |
IM, intramuscularly.
Reproduced from Sabaratnam Arulkumaran, Lesley Regan, Aris Papageorghiou, Ash Monga, and David Farquharson, (Chapter 8) in Oxford Desk Reference Obstetrics and Gynaecology, Oxford University Press, pp, 259-260 with permission from Oxford University Press,