Advertisement

COVID-19 vaccination in pregnancy: early experience from a single institution

      OBJECTIVE

      Pregnant women are at increased risk for morbidity owing to infection with the COVID-19 virus.
      • Ellington S
      • Strid P
      • Tong VT
      • et al.
      Characteristics of women of reproductive age with laboratory-confirmed SARS-CoV-2 infection by pregnancy status—United States, January 22-June 7, 2020.
      Vaccination presents an important strategy to mitigate illness in this population. However, there is a paucity of data on vaccination safety and pregnancy outcomes because pregnant women were excluded from the initial phase III clinical trials. Our objective was to describe the maternal, neonatal, and obstetrical outcomes of women who received a messenger RNA (mRNA) COVID-19 vaccination while pregnant during the first 4 months of vaccine availability.

      STUDY DESIGN

      This was an institutional review board–approved descriptive study of pregnant women at New York University Langone Health who received at least 1 dose of an mRNA COVID-19 vaccination approved by the US Food and Drug Administration (FDA) (Pfizer-BioNTech or Moderna) from the time of the FDA Emergency Use Authorization to April 22, 2021. Eligible women were identified via search of the electronic medical record (EMR) system. Vaccine administration was ascertained via immunization records from the New York State Department of Health. Women were excluded if they were vaccinated before conception or during the postpartum period. Charts were reviewed for maternal demographics and pregnancy outcomes. Descriptive analyses were performed using the R software version 4.0.2 (The R Foundation, Boston, MA).

      RESULTS

      We identified 424 pregnant women who received an mRNA vaccination. Of those, 348 (82.1%) received both doses and 76 (17.9%) received only 1 dose. The maternal characteristics and vaccination information are shown in Table 1. Of the included women, 4.9% had a history of a confirmed COVID-19 diagnosis before vaccination. After vaccination, no patient in our cohort was diagnosed with COVID-19. In terms of the pregnancy outcomes, 9 women had spontaneous abortions, 3 terminated their pregnancies, and 327 have ongoing pregnancies. Of the women included, 85 delivered liveborn infants. There were no stillbirths in our population. Of the 9 spontaneous abortions, 8 occurred during the first trimester at a range of 6 to 13 weeks’ gestation. There was 1 second trimester loss. The rate of spontaneous abortion among women vaccinated in the first trimester was 6.5%. The 327 women with ongoing pregnancies have been followed for a median of 4.6 weeks (range, 0–17 weeks) following their most recent dose. A total of 113 (34.6%) women, initiated vaccination during the first trimester, 178 (54.4%) initiated vaccination during the second trimester, and 36 (11.0%) during the third trimester. Following the vaccination, 2 fetuses (0.6%) developed intrauterine growth restriction, whereas 5 (1.5%) were diagnosed with anomalies. Outcomes for the 85 women who delivered are shown in Table 2. Of the women who delivered, 18.8% were diagnosed with a hypertensive disorder of pregnancy. The rate of preterm birth was 5.9%. One preterm delivery was medically indicated, whereas the remaining 3 were spontaneous. A total of 15.3% of neonates required admission to the neonatal intensive care unit (NICU). Of the NICU admissions, 61.5% were because of hypoglycemia or an evaluation for sepsis. Other reasons for admission included prematurity, hypothermia, and transient tachypnea of the newborn. Of all the neonates, 12.2% were small for gestational age (SGA) per the World Health Organization standards.

      CONCLUSION

      This series describes our experience with women who received an mRNA COVID-19 vaccine during pregnancy. In line with other published findings,
      • Shimabukuro TT
      • Kim SY
      • Myers TR
      • et al.
      Preliminary findings of mRNA COVID-19 vaccine safety in pregnant persons.
      we observed no concerning trends. There were no stillbirths. Our 6.5% rate of spontaneous abortion is within the expected rate of 10%,
      American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Gynecology
      ACOG Practice Bulletin No. 200: early pregnancy loss.
      and our preterm birth rate of 5.9% is below the national average of 9.5%.
      • Ferré C
      • Callaghan W
      • Olson C
      • Sharma A
      • Barfield W.
      Effects of maternal age and age-specific preterm birth rates on overall preterm birth rates—United States, 2007 and 2014.
      Our rate of pregnancy-related hypertensive disorders is higher than our baseline institutional rate of 9.5%, however, this may be because of the underlying characteristics of our study population or skewing of our small sample size. Our 12.2% rate of SGA neonates is near the expected value based on the definition that 10% of neonates will be SGA at birth. The NICU admission rate is at par with our institutional rate of 12%. To date, most women in this series have had uncomplicated pregnancies and have delivered at-term. Strengths of this study include using the EMR system to identify subjects and gather data. We did not rely on self-enrollment and self-report, thereby reducing selection and recall bias. By performing manual chart reviews, we obtained detailed and reliable information about individual patients. One limitation of this study is the lack of a matched control group consisting of unvaccinated pregnant women and therefore direct conclusions could not be drawn about the relative risks of complications. In addition, our cohort is small and may not be generalizable. Finally, many women included are healthcare workers who had early access to vaccinations. As more pregnant women become eligible for the COVID-19 vaccinations, there is an urgent need to report on the maternal, neonatal, and obstetrical outcomes of COVID-19 vaccinations during pregnancy. The results of this study can be used to counsel and reassure pregnant patients facing this decision.
      Table 1Study population demographics and vaccination characteristics
      Trostle. COVID-19 vaccination in pregnancy. Am J Obstet Gynecol MFM 2021.
      Study variableTotal study population

      (N=424)
      Age (y)35 (6)
      Age ≥35 y220 (51.9)
      Race or ethnicity

       White

       Black

       Asian

       Hispanic or Latino

       Other or not recorded


      262 (61.8)

      22 (5.2)

      57 (13.4)

      37 (8.7)

      46 (10.8)
      Prepregnancy BMI (kg/m2)23.2 (5.2)
      The n for BMI is 371; a total of 53 values were missing.
      BMI ≥30 kg/m242 (11.3)
      The n for BMI is 371; a total of 53 values were missing.
      Prepregnancy comorbidities

       Chronic hypertension

       Pregestational diabetes

       Cardiac disease

       Respiratory disease

       Autoimmune disease

       Malignancy (past or present)


      28 (6.6)

      5 (1.2)

      10 (2.4)

      38 (9.0)

      19 (4.5)

      10 (2.4)
      Nulliparous267 (63.0)
      Insurance

       Private

       Public

       Unknown or uninsured


      407 (96.0)

      16 (3.8)

      1 (0.2)
      History of COVID-19 diagnosis21 (4.9)
      Vaccination type

       Pfizer-BioNTech

       Moderna


      332 (78.3)

      92 (21.7)
      Gestational age at first dose (wk)21.0 (16.4)
      Gestational age at second dose (wk)23.9 (17.6)
      Trimester at vaccination initiation

       First (<14 wk)

       Second (14–27 wk)

       Third (>28 wk)


      124 (29.2)

      193 (45.5)

      107 (25.2)
      Data are reported as number (percentage) or median (interquartile range).
      BMI, body mass index.
      a The n for BMI is 371; a total of 53 values were missing.
      Table 2Characteristics and outcomes of women who delivered
      Trostle. COVID-19 vaccination in pregnancy. Am J Obstet Gynecol MFM 2021.
      Study variableWomen who delivered (n=85)
      Vaccine type

       Pfizer-BioNTech

       Moderna


      65 (86.5)

      20 (23.5)
      Trimester at vaccination initiation

       First (<14 wk)

       Second (14–27 wk)

       Third (>28 wk)


      0

      14 (16.5)

      71 (83.5)
      Time from vaccination until delivery (wk)2.86 (0.29–12.7)
      Both vaccination doses completed before delivery68 (80)
      Fetal or neonatal demise0
      Gestational age at delivery (wk)39.3 (33.0–41.7)
      Preterm delivery <37 wk5 (5.9)
      Mode of delivery

       Vaginal delivery

       Cesarean delivery


      55 (64.7)

      30 (35.3)
      Obstetrical complications

       Pregnancy-related hypertensive disorders

       Preterm labor

       Preterm prelabor rupture of membranes

       Abruption

       Placenta previa


      16 (18.8)

      0

      2 (2.4)

      1 (1.2)

      1 (1.2)
      Neonatal intensive care unit admission13 (15.3)
      Birthweight (g)3374 (1910–4360)
      Small for gestational age10 (12.2)
      Congenital anomalies2 (1.2)
      Data are reported as number (percentage) or median (range).

      References

        • Ellington S
        • Strid P
        • Tong VT
        • et al.
        Characteristics of women of reproductive age with laboratory-confirmed SARS-CoV-2 infection by pregnancy status—United States, January 22-June 7, 2020.
        MMWR Morb Mortal Wkly Rep. 2020; 69: 769-775
        • Shimabukuro TT
        • Kim SY
        • Myers TR
        • et al.
        Preliminary findings of mRNA COVID-19 vaccine safety in pregnant persons.
        N Engl J Med. 2021; 384: 2273-2282
        • American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Gynecology
        ACOG Practice Bulletin No. 200: early pregnancy loss.
        Obstet Gynecol. 2018; 132 (e197–207)
        • Ferré C
        • Callaghan W
        • Olson C
        • Sharma A
        • Barfield W.
        Effects of maternal age and age-specific preterm birth rates on overall preterm birth rates—United States, 2007 and 2014.
        MMWR Morb Mortal Wkly Rep. 2016; 65: 1181-1184