Practical Issues in Obstetrics: Vaccination and Weight Gain

Educational Objectives

The goal of this program is to improve adherence to guidelines and recommendations for vaccinations during pregnancy and management for weight gain in pregnancy. After hearing and assimilating this program, the clinician will be better able to:

1.   List examples of each type of vaccine.

2.   Discuss indications for immunization during pregnancy.

3.   Explain the purpose of the National Childhood Vaccine Injury Act.

4.   Counsel pregnant women about appropriate weight gain during pregnancy.

5.   Encourage behaviors associated with successful weight maintenance in pregnancy.

Faculty Disclosure

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the plan­ning committee to disclose relevant financial relationships within the past 12 months that might create any personal con­flicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Silverman was recorded at the 64th Obstetrical and Gynecological Assembly of Southern California, sponsored by the Obstetrical and Gynecological Assembly of Southern California, and held April 3-4, 2009, in Los Angeles, CA. Dr. Stot­land was recorded at Antepartum & Intrapartum Management, sponsored by the University of California, San Francisco, School of Medicine, and held on June 11-13, 2009, in San Francisco, CA. The Audio-Digest Foundation thanks the speak­ers and the sponsors for their cooperation in the production of this program.

Vaccination in Pregnancy

Neil S. Silverman, MD, Clinical Professor, Obstetrics and Gynecology, David Geffen School of Medicine, Uni­versity of California, Los Angeles

Historical background: in late 1800s, Edward Jenner used material from cowpox lesions to vaccinate boy 8 yr of age; in late 19th century, Louis Pasteur vaccinated boy 9 yr of age bitten by rabid dog (postexposure vaccination); World Health Assembly certified world free of smallpox in 1980; universal polio immunization has eradicated nat­urally-occurring polio in United States and Western Hemisphere

Types of vaccination: active and passive

Whole organism: live attenuated  —  allowed to replicate and culture for extended period; antigenic, but not infec­tious; eg, measles, mumps, and rubella (MMR), varicella, yellow fever, and intranasal influenza vaccines; inacti­vated (killed)  — hepatitis A, meningococcal, and intramuscular (IM) influenza vaccines

Purified subcellular fractions of organisms: protein shell from encapsulated organisms without infectious agents (theoretically, no risk for infection); eg, Haemophilus influenza type b (Hib), pneumococcal vaccines

Genetically engineered recombinant protein: vaccine contains only re-engineered proteins (no actual viral mate­rial); eg, hepatitis B vaccine

Inactivated endotoxin: tetanus toxoid vaccine

Promoting immunization: national and global vaccination efforts traditionally focused on reducing morbidity and mortality due to childhood illnesses; 1994 report cited »500 deaths from vaccine-preventable illness in children, compared to 50,000 to 70,000 deaths in adults; as recently as 4.5 yr ago, >50% of significant vaccine-preventable illness occurred in individuals >15 yr of age; immunization services not traditionally included in obstetric and gy­necologic care; professional societies addressing benefit of vaccination for women and long-term health of child

Advisory Committee for Immunization Practices (ACIP): charter  —  “shall provide advice and guidance to the Secretary of Health and Human Services, the assistant Secretary for Health, and Director of Centers for Disease Control and Prevention (CDC) regarding the most appropriate selection of vaccines and related agents for effective control of vaccine-preventable diseases”; ACIP also to address pregnant and breastfeeding women; considerations during pregnancy and breastfeeding  —  disease burden for pregnant women, fetuses, newborns, and young infants; goal of vaccination protection of mother, fetus, or neonate; need adequate immunogenicity, efficacy, and safety data, and data on trimester-specific safety

Influenza and pregnancy: immunization with trivalent inactivated influenza vaccine (TIV) recommended for all pregnant women; increased morbidity and hospitalization rates related to influenza for pregnant women in every trimester, compared to rates in nonpregnant women; with comorbidities (eg, respiratory disease), risk ratio 3 times higher in first trimester and 8 times higher in third trimester; increased risk for maternal death reported in pandemics; live attenuated nasal vaccine contraindicated in pregnancy and in women >65 yr of age; data show antivirals not always available to treat patients who have not been vaccinated

Influenza A virus: H1N1  predominant strain in community during last 2 yr; strains characterized by hemagglutinin (H) and neuraminidase (N) proteins on surface of virus; antibodies generated by vaccination must be H- and N- spe­cific for predicted dominant virus strain in particular year; 92% of H3N2 (predominant strain in 2006) became resis­tant to adamantanes (eg, Amantidine, Rimantidine; used as antiviral treatment and for prophylaxis); CDC surveillance shows 98% of H1N1 strains now resistant to oseltamivir (Tamiflu); antibiotic resistance not caused by overexposure to antibiotic (induced resistance), but rather spontaneous mutation that occurred when neuraminidase inhibitors developed; mutated virus demonstrates enhanced propagation as well as resistance; H1N1 virus remains sensitive to zanamivir (Relenza), but fewer people can tolerate it; flu vaccine not recommended for children <6 mo of age; pregnant women shown to have protective levels of anti-influenza antibodies after vaccination; theoretic ev­idence of passive transfer of antibodies from vaccinated women to neonates; retrospective clinic-based study (2004) showed nonsignificant trend toward fewer episodes of respiratory illness among newborns of vaccinated pregnant women;  2008 randomized controlled trial in Bangladesh showed 63% lower risk for laboratory-confirmed neonatal influenza in children of vaccinated mothers through 6 mo of age (first study to definitively show benefit to women and children)

Barriers to influenza vaccination in pregnant women: lack of information; variations in level of concern about influ­enza from year to year; concerns about risk in pregnancy; provider concerns about reimbursement and litigation; confusion over recommendations

Recommendations: inconsistent in the past; currently, recommendation to vaccinate pregnant women during influ­enza season in any trimester of pregnancy

National Childhood Vaccine Injury Act (NCVI Act): established by Congress in mid 1980s; began operation 1988; no-fault Federal compensation program; alternative to tort system; table of injury established for each vaccine; fi­nanced by $0.75 tax per antigen and each tax must be passed by Congress; time limits for inquiries; covers all vac­cines included in childhood vaccination schedule, regardless of who administering and who receiving; also pertains to hepatitis B, varicella, tetanus, and influenza vaccines; requires health care provider to record vaccine, manufac­turer, lot number, and name and title of person administering vaccine; requires reporting of adverse vaccination re­actions to Vaccine Adverse Event Reporting System (VAERS); Vaccine Information Statement (VIS) should be given to patients for each vaccination

Tetanus, diphtheria, and pertussis (DTP) vaccine: recommendation for tetanus booster every 10 yr unchanged; no exception for pregnancy; DTP typically childhood vaccine; adults receive tetanus-diphtheria (Td) booster not DTP booster; rates of pertussis infection have soared in United States, despite childhood vaccination; adults and adolescents accounted for two-thirds of cases in 2006; newer vaccine tetanus, diphtheria, and acellular pertussis-containing preparation (Tdap); compensates for waning immunity from older vaccine

Recommendation: all adults receive one booster dose of Tdap to provide protection against pertussis if last Td ³2 yr ago; new CDC guidelines recommend postpartum Tdap vaccination for all women, including those breastfeed­ing, to allow for maximum vaccination rates; hospitals encouraged to incorporate into postpartum protocols be­fore patient discharged

Hepatitis vaccines: hepatitis B  —  recombinant vaccine; no contraindication during pregnancy; women with risk fac­tors and health care workers should receive regardless of pregnancy status; women who have started vaccine se­ries should continue and complete during pregnancy

Hepatitis A: inactivated virus vaccine; no contraindication in pregnancy; food handling in restaurants primary source of hepatitis A outbreaks; speaker recommends vaccination against hepatitis A for all residents of urban settings

Hepatitis C: women diagnosed with hepatitis C should be tested for hepatitis A and B and vaccinated if not immune (higher morbidity if patient coinfected with another hepatitis virus)

Travel vaccines and pregnancy: consideration should be given to necessity of travel during pregnancy; patient should know MMR and tetanus status; standard travel vaccines  —  many not contraindicated in pregnancy; hepati­tis, meningococcal, typhoid (may be more serious in pregnancy) and polio (use inactivated vaccine, not oral); yel­low fever  —  live attenuated vaccine; no adverse effects reported; malaria prophylaxis  —important if traveling to endemic areas; all protocols acceptable in pregnancy, except primaquine

Inadvertent vaccination: issue arises when live attenuated vaccine (MMR or varicella) administered to woman with undiagnosed early pregnancy; rubella  —  no proven cases of congenital rubella syndrome (CRS) associated with vaccination with current RA27/3 vaccine in either United States or United Kingdom registries; varicella  —  Varivax registry data report no cases of congenital varicella syndrome attributable to vaccination; inadvertent varicella or rubella vaccination during early pregnancy should not be regarded as reason to terminate pregnancy

Weight Gain in Pregnancy

Naomi E. Stotland, MD, Assistant Professor, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, School of Medicine

Guidelines for weight gain in pregnancy: Institute of Medicine (IOM) released new guidelines May 2009; in past, main concern to prevent low birth weight by having women gain adequate amount of weight during pregnancy; cur­rent obesity epidemic in United States increasing concern about excessive weight gain in pregnancy and impact on mother and fetus; review showed guidelines used in past for weight gain in pregnancy consistent with best outcomes; previous guidelines did not state upper limit of weight gain for obese women; new guidelines recommend obese woman gain 11 to 20 lb during pregnancy (previously ³15 lb); new guidelines use World Health Organization (WHO) body mass index (BMI) cutoffs; women previously in normal BMI category now in overweight category

Outcomes of inadequate pregnancy weight gain: intrauterine growth restriction (IUGR); infant small for gesta­tional age (SGA); spontaneous preterm birth; preterm premature rupture of membranes (PPROM); neonatal mor­bidity (only with severely inadequate weight gain)

Outcomes associated with excessive weight gain: women who gain excessive weight in first half of pregnancy more likely to be diagnosed with gestational diabetes and impaired glucose tolerance; postdate pregnancy more common in women who have prepregnancy obesity as well as excessive weight gain during pregnancy; prolonged labor (in­dependent of birth weight); higher cesarean delivery rate; higher failure of vaginal birth after cesarean delivery (VBAC); hypertensive disorders of pregnancy; neonatal outcomes  —  preterm birth (may be iatrogenic); failure to initiate or sustain breastfeeding; postpartum weight retention

Excessive weight gain: »42% of normal-weight women and 54% of overweight women exceed guidelines; »50% of obese women in California have weight gain above IOM guidelines (guidelines available on IOM’s website)

Prenatal advice: survey study showed that receiving correct advice about weight gain associated with actual weight gain within guidelines (when controlling for sociodemographic factors); approximately one-third of women reported receiving no advice about how much weight to gain; focus group study of prenatal care providers showed health care providers uncomfortable talking about weight gain; providers reported waiting for patient to initiate topic or discuss­ing  only if weight gain excessive; dietitians  —  should be part of team approach; be aware that patient may get differ­ent information from heath care provider and dietitian (dieticians required to practice under strict guidelines); dietary counseling  —  patients often unaware of number of caloriesthey consume; assist patient in identifying sources of hid­den calories (eg, fruit juices) in diet

Studies: interventions to prevent excessive weight gain  —Polley et al showed reduced excessive weight gain only in subgroup of women with normal prepregnancy BMI; Olson et al showed benefit only in low-income subgroup of women, suggesting health education more beneficial for women with less education; Asbee et al showed lower weight gain on average in intervention group, but no difference in primary outcome (ie, keeping weight gain within IOM guidelines); interventions to restrict weight gain in obese women  —  data show exercise effective at reducing weight gain in obese women with gestational diabetes; Video Doctor  —  laptop-based interactive intervention; gen­erates provider alert sheet to reinforce counseling; results of data at »20 wk of pregnancy showed no difference in weight gain, but women self-reported improved diet and physical activity

Exercise: conflicting studies about association between exercise and weight gain; 2 studies among obese women showed reduced weight gain compared to nonexercising controls; American College of Obstetricians and Gynecol­ogists (ACOG) committee opinion  —  “³30 minutes of moderate exercise a day should occur on most, if not all, days of the week”

Behaviors associated with successful weight maintenance: self-monitoring of weight at home (focus should be on healthy lifestyle practices rather than on weight); pedometer useful tool in motivating patient to increase ex­ercise; consuming fewer energy-dense foods; soup or salad before meal can reduce overall caloric intake at meal and increase micronutrients; overweight or obese women often malnourished (especially in low-income popula­tion) because of highly processed (high calorie, low nutrient) foods; encourage consumption of fruits and vege­tables for proper fetal development and weight maintenance; women with higher consumption of sweets consumed more calories and energy-dense foods and had higher weight gain during pregnancy

Summary of recommendations: measure prepregnancy BMI at first prenatal visit and discuss with patient; set target weight gain at first visit and discuss appropriate weekly weight gain throughout pregnancy; encourage self-monitoring of weight at home; review diet and exercise behaviors and let patient choose small goals; weigh patient, graph weight at each visit, and discuss with patient; refer to dietician if possible, but health care provider should reinforce nutritional advice; beware of conflicting advice or messages from dietician, partner, family, and provider; issue of weight gain in pregnancy should not be stressful for patients, but avoiding topic entirely can cause patient to become anxious; several ongoing studies looking at optimal weight gain range for obese women; question of whether extreme restriction of cal­ories safe remains unanswered

Suggested Reading

Asbee SM et al: Preventing excessive weight gain during pregnancy through dietary and lifestyle counseling: a randomized controlled trial. Obstet Gynecol 113(2 Pt 1):305, 2009; Ayoub DM et al: A closer look at influenza vaccination during pregnancy. Lancet Infect Dis 8(11):660, 2008; Brawarsky P et al: Pre-pregnancy and pregnancy-related factors and the risk of excessive or inadequate gestational weight gain. Int J Gynaecol Obstet 91(2):125, 2005; Bruhn K et al: Administration of vaccinations in pregnancy and postpartum. MCN Am J Matern Child Nurs 34(2):98, 2009; Carroll ID et al: Pre-travel vaccination and medical prophylaxis in the pregnant traveler. Travel Med Infect Dis 6(5):259, 2008; Chu SY et al: Gesta­tional weight gain by body mass index among US women delivering live births, 2004-2005: fueling future obesity. Am J Obstet Gynecol 200(3):271, 2009; Cogswell ME et al: Medically advised, mother’s personal target, and actual weight gain during pregnancy. Obstet Gynecol 94(4):616, 1999; Mak TK et al: Influenza vaccination in pregnancy: current evidence and selected national policies. Lancet Infect Dis 8(1):44, 2008; Naleway AL et al: Delivering influenza vaccine to pregnant women. Epidemiol Rev 28:47, 2006; Polley BA et al: Randomized controlled trial to prevent excessive weight gain in preg­nant women. Int J Obes Relat Metab Disord 26(11):1494, 2002; Stotland NE: Obesity and pregnancy. BMJ 337, 2008; Stotland NE et al: Body mass index, provider advice, and target gestational weight gain. Obstet Gynecol 105(3):663, 2005; Zaman K et al: Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med 359:1555, 2008.