Pregnancy, Asthma and COVID-19
DOES PREGNANCY INCREASE THE NEED FOR CRITICAL CARE IN THE SETTING OF COVID-19 INFECTION?
Historically, pregnant individuals have been thought to be at increased risk of severe morbidity and mortality from specific respiratory infections, such as flu and SARS. As of 2023, more than 163,140 infections and 257 maternal deaths have occurred in pregnant women in the United States (CDC).
Studies have shown a high prevalence of asymptomatic COVID-19 infection in pregnant women. In one study, 75% were asymptomatic on admission and 63.5% of these women remained asymptomatic throughout hospitalization. (Hcini, Cosma)
However, for those pregnant women with symptomatic COVID-19 infection, intensive care unit (ICU) admission, invasive ventilation, extracorporeal membrane oxygenation, and death were more likely than in nonpregnant women.
High body mass index, chronic hypertension, and pre-existing diabetes appear to be risk factors associated with severe COVID-19 in pregnancy as well as poorer outcomes including fetal death, preterm birth and low birth weight. (Allotey, Smith)
IS TIMING OF DELIVERY AFFECTED BY COVID-19?
Having severe symptoms or complications from any illness might affect timing of delivery. For women with suspected or confirmed COVID-19 in the third trimester who recover, it is reasonable to attempt to postpone elective delivery until a negative test result is obtained in an attempt to avoid transmission to the neonate.
DOES COVID-19 PRESENT AN INCREASED RISK OF ADVERSE PERINATAL AND FETAL OUTCOMES?
Maternal SARS-CoV-2 infection may lead to perinatal complications directly or indirectly through placental dysfunction. Placental abnormalities such as malperfusion and functional impairment have been reported in pregnant women with COVID-19, potentially leading to outcomes such as preterm birth, intrauterine growth restriction, caesarean delivery, low birth weight and possibly early pregnancy loss (Cavalcante, Prabhu)
Using data from the International Registry of Coronavirus Exposure in Pregnancy (IRCEP), the relative risk of major congenital malformations in those pregnant patients with COVID-19 infection during the first trimester did not differ significantly from that reported by an internal reference group with negative SARS-CoV-2 tests. (Hernandez-Diaz)
Preterm birth has been reported in several studies to be increased in those with symptomatic and asymptomatic infection with prevalence reported up to 11.5%. (Adhikari, Ahlberg, Allotey, Mullins)
What is evident is that severe to critical COVID-19 infection during pregnancy is associated with higher rates of adverse neonatal outcomes and strongly associated with neonatal intensive care unit admission and fetal growth restriction compared to those pregnant people with mild disease. (Hamidi)
CAN MATERNAL SARS-COV-2 INFECTION BE TRANSMITTED TO THE FETUS?
In reports of a limited number of infants born to women with COVID-19 around the time of delivery, most newborns have not had evidence of infection. However, a small number of newborns have tested positive for the virus soon after delivery. This suggests the possibility that the virus could pass from a mother to a baby during pregnancy. The PRIORITY study described 263 infants born to mothers with confirmed SARS-CoV-2 during pregnancy, the estimated incidence of a positive infant SARS- CoV-2 test was low at 1.1%. Other studies support that this risk is quite low.
ARE THERE SPECIAL CONSIDERATIONS FOR PREGNANT WOMEN WITH ASTHMA?
Few data exist to indicate that having asthma is associated with an increased risk of becoming infected with COVID-19 or a more severe course in the non-pregnant infected patient. A large prospective population-based cohort study in Denmark of over 80,000 pregnancies, found that asthma was a significant risk factor for infection with severe acute respiratory syndrome with COVID (OR 2.12, 95%CI 1.41-3.41). (Aabakke) The CDC does indicate that those with moderate to severe asthma might be at a higher risk for severe illness from COVID-19.
Current recommendations emphasize the need to maintain asthma control during pregnancy. Reducing controller therapy could put pregnant women with asthma at increased risk of an asthma exacerbation necessitating medical care, which could then put them at an increased risk of being exposed to COVID-19.
IS BREASTFEEDING SAFE DURING COVID-19 INFECTION?
Breast milk provides protection against serious childhood infections. Women are often encouraged to continue breastfeeding or provide breast milk even when they are sick with a virus, such as the flu. Most case reports have detected little or no virus in the breastmilk of infected mothers. (Chambers, Peng) In a review of 46 COVID-19 positive mothers, of breast milk samples that tested positive for COVID-19, only one infant tested positive for the virus (Centeno-Tablante). This suggests that breast milk may not be a potential source of infection for the infant.
ARE THERE ANY DATA ON THE SAFETY OF REMDESIVIR OR MONOCLONAL ANTIBODIES IN THE MANAGEMENT OF CRITICALLY ILL PREGNANT COVID-19 PATIENTS?
Data on the use of remdesivir or other monoclonal antibodies in pregnancy are limited. Manufacturer safety data indicate no reproductive developmental toxicity in animals at clinically relevant doses. Embryonic toxicity was only noted when systemically toxic doses were administered to female animals before conception. One case report describes one pregnant patient who received compassionate use of remdesivir and developed transaminitis, which is a noted side effect of remdesivir (Malderelli).
Levey, et al reported a retrospective cohort study of 86 pregnant patients who either tested positive for SARS-CoV-2 or had a known exposure to a COVID-19-positive person and were therefore eligible for an infusion of casirivimab and imdevimab (REGEN-COV), a monoclonal antibody therapy. Comparing the outcomes in 36 patients who received the treatment versus 50 who did not, administration of REGEN-COV did not increase adverse maternal, neonatal, or obstetrical outcomes. (Levy)
ARE THERE ANY DATA ON THE SAFETY OF NIRMATRELVIR-RITONAVIR (PAXLOVID) DURING PREGNANCY?
In a cross-sectional study of 35 vaccinated pregnant patients who received Paxlovid, there were no significant adverse outcomes observed. (Lin).
SHOULD PREGNANT AND LACTATING WOMEN RECEIVE THE COVID-19 VACCINE?
None of the available vaccines were specifically tested in pregnant women or in those who were breastfeeding. Without data, having a shared decision-making dialogue with the pregnant patient regarding receiving the vaccine that considers exposure risk and underlying conditions will be essential. This is supported by the American College of Obstetricians and Gynecologists (ACOG) who recommends that COVID-19 vaccines should not be withheld from pregnant individuals who meet criteria for vaccination based on Advisory Committee on Immunization Practices (ACIP)-recommended priority groups and that pregnant individuals should be free to make their own decision in conjunction with their clinical care team.
As of September 2021, 31% of pregnant people were fully vaccinated before or during their pregnancy. (CDC)
Assuming that the vaccination is at least 95% effective, one maternal death could be prevented by approximately 700 immunizations in the United States. (Kalafat)
A U.S. survey of 662 pregnant women found that 77.9% reported having already been vaccinated against influenza during the 2020-2021 season, and 58.3% said they would accept the COVID-19 vaccine while pregnant. Concern for the fetus and vaccine side effects were most common reasons for those declining vaccination. (Levy)
ARE THERE SAFETY DATA ON THE USE OF COVID-19 VACCINES IN PREGNANCY?
Using data from the V-safe program, the CDC reviewed preliminary data on over 35,000 women who identified as pregnant after their vaccine. Data on almost 4,000 who participated in the pregnancy registry did not show any safety signals of concern, and outcomes were similar to studies on pregnant women before the pandemic.
Reports of thrombosis with thrombocytopenia (TTS) have been associated with the Johnson & Johnson-Janssen vaccine. Although the overall risk of thrombosis is increased during pregnancy and postpartum, the mechanism is distinct from pregnancy-associated thrombosis and therefore there are no specific concerns for pregnant women. (ACOG)
There appears to be no increased risk of spontaneous abortion in pregnant women who received the mRNA COVID-19 vaccine. (Bernard, Kharbanda, Zauche)
COVID-19 vaccination was not associated with small for gestational age at birth, preterm birth (Fell, Goldshtein, Lipkind, Magnus) or congenital anomalies. (Goldshtein)
ARE THERE DATA REGARDING THE SAFETY OR EFFECTIVENESS OF BOOSTER DOSES OF COVID-19 VACCINES?
Between September 2021 and March 2022, there were 323 reports of adverse events in pregnant people receiving the booster dose of COVID-19 vaccine.
Using data from Vaccine Safety Datalink, an observational, case-control, surveillance study comparing spontaneous abortion cases and ongoing pregnancy controls found the receipt of the third mRNA COVID-19 vaccine was not associated with spontaneous abortion in a 28 day window (AOR 0.94,95%CI (0.86-1.03) (Kharbanda) Another study found no obstetric or lactation concerns after vaccination. (Kacklikis)
HAS THE COVID-19 VACCINE BEEN SHOWN TO IMPROVE PERINATAL OUTCOMES IN PREGNANT PERSONS?
A large retrospective cohort study from Australia found that COVID-19 vaccination during pregnancy, compared with unvaccinated women, was associated with a lower rate of stillbirth (0.2% vs. 0.8%, aOR 0.18, 95%CI 0.09-0.37) and a significant reduction in total preterm births (5.1% vs.9.2%, aOR 0.60,95%CI 0.51-0.71). Vaccinated women were also significantly less likely to have an infant with a major congenital anomaly (2.4% vs 3.0%, aOR 0.72, 95%CI 0.56-0.94) (HUI)
WHICH TRIMESTER OF PREGNANCY IS IDEAL FOR RECEIVING THE COVID-19 VACCINE?
In an ideal scenario, vaccinating a pregnant patient should result in a maximum coverage period during pregnancy while providing protection through delivery. Another issue is the protection that maternal vaccination during pregnancy provides for the infant.
In a prospective cohort study of women who received mRNA vaccination during the second trimester of pregnancy, neonatal IgG titers were higher than maternal titers, representing 100% placental antibody transfer (Kugelman)
COVID-19 vaccination during the third trimester was associated with a strong maternal humoral IgG response and early compared with late third trimester is preferable (Beharer, Rottenstreich)
CAN COVID-19 VACCINATION DURING PREGNANCY PROVIDE PROTECTION TO THE UNBORN BABY?
Vaccines such as influenza and TdaP have been recommended for use during pregnancy and have been shown to protect newborns via passage of antibodies through the placenta.
While it is unclear at this point whether COVID-19 vaccination could also protect the infant from the infection by passive transfer of antibodies, reports have shown the presence of SARS-CoV-2 IgG antibodies detectable in cord blood following maternal vaccination and a persistence of anti-SARS-CoV2- antibodies in the infant at 2 weeks, 6 weeks, 3 months, and 6 months of age (Mangat, Paul)
The results of a Norwegian population-based cohort study suggested a lower risk of a positive test for SARS-CoV-2 during the first 4 months of life among infants born to mothers who were vaccinated during pregnancy (Carlsen)
IS COVID-19 VACCINATION SAFE WHILE BREASTFEEDING?
Although lactating people were excluded from vaccination trials, many received the vaccine after its release to the public. In a study of lactating people who received two-dose Pfizer/Biontech vaccine, 61.8% of breastmilk samples tested positive for anti-SARS-CoV-2 specific IgA at 2 weeks after the first dose and 86.1% at 1 week after the booster dose. (Perl) One study found that vaccination during lactation was safe and posed no risk to mother or baby. Some women observe a temporary increase or decrease in milk supply without long-term effects. (Muyldermans)
IS THERE INFORMATION ON HEALTH EQUITY AND COVID-19 VACCINE ACCESS?
Pregnant minoritized women in the US experience greater mortality due to COVID-19-associated complications compared to non-Hispanic whites. (Thoma) In 2020 compared to 2019, there was a 44% increase in maternal death among Hispanic women, 25.7% increase among non-Hispanic Black women, and a 6.1% increase among non-Hispanic White women, largely attributed to the COVID-19 pandemic. (Hoyert) More concerning is that young non-Hispanic Black women have the highest level of vaccine hesitancy, as a result of reduced vaccine confidence. (Kiefer) Therefore there is a need to improve outreach and engagement among pregnant minority women who might be at a higher risk for severe health outcomes because of COVID-19. However, decision-making when it comes to vaccine acceptance can be complex and involve cultural, social, or spiritual factors. Several strategies have been published as well as suggested by the CDC. Some strategies might include an education and information component, childcare, food vouchers, gift cards, and baby products. Health provider engagement might be one of the most important strategies to provide awareness, address misinformation, and improve access to vaccinations. (Alcendor)
ARE THERE ONGOING STUDIES TO WHICH PREGNANT WOMEN COULD BE REFERRED?
As part of their pregnancy studies, the organization MotherToBaby is interested in examining the short and long-term effects of COVID-19 in pregnancy and breastfeeding, as well as COVID-19 vaccination in pregnancy or during breastfeeding. This study will consist of phone calls over the course of the pregnancy and post-delivery or while breastfeeding, release of medical records related to the pregnancy and infant’s development, and collection of breast milk samples. If you have a pregnant or breastfeeding patient with COVID-19, or who has been vaccinated please consider enrolling them at mothertobaby.org or by calling (877) 311-8972.
The Vaccines and Medications in Pregnancy Surveillance System (VAMPSS) also is continuing to study asthma medications during pregnancy. VAMPSS is a nationwide post-marketing surveillance system established to comprehensively monitor the use and safety of vaccines and medications during pregnancy, coordinated by the AAAAI. You can learn more about VAMPSS at the AAAAI website. If you have a pregnant patient with asthma, please consider enrolling them in the VAMPSS studies at mothertobaby.org or by calling (877) 311-8972.
REFERENCES
CDC COVID-19 Response Team; Food and Drug Administration Allergic reactions including anaphylaxis after receipt of the first dose of Moderna COVID-19 vaccine—United States, December 21, 2020-January 10, 2021. MMWR Morb Mortal Wkly Rep. 2021;70:125–129.
CDC Health Alert Network-00453. COVID-19 vaccination for pregnant people to prevent serious illness, deaths, and adverse pregnancy outcomes from COVID-19. 2021
COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) (unpublished
COVID Data Tracker. Vaccinations Among Pregnant People.
Aabakke et al. SARS-CoV-2 infection in pregnancy in Denmark –characteristics and outcomes after confirmed infection in pregnancy: a nationwide, prospective, population-based cohort study. Acta Obstet Gynecol Scand. 2021
Adhikari et al. Pregnancy outcomes among women with and without severe acute respiratory syndrome coronavirus 2 infection. JAMA Netw Open. 2020
Ahlberg et al. Association of SARS-CoV-2 Test Status and Pregnancy Outcomes. JAMA. 2020
Alcendor et al. The COVID-19 Vaccine and Pregnant Minority Women in the US: Implications for Improving Vaccine Confidence and Uptake. Vaccines. 2022
Allotey et al. Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. BMJ 2020
Behariar et al. Efficient maternal to neonatal transfer of antibodies against SARS-CoV-2 and BNT16 2b2 mRNA COVID-19 vaccine. J Clin Invest. 2021
Bernard et al. First-trimester mRNA COVID-19 vaccinations and risk of major congenital anomalies. JAMA Netw Open. 2025
Carlsen et al. Association of COVID -19 vaccination during pregnancy with incidence of SARS-CoV-2 infection in infants. JAMA Int Med. 2022
Cavalcante, et al. Maternal immune responses and obstetrical outcomes of pregnant women with COVID-19 and possible health risks of offspring. J Reprod Immunol. 2021
Centeno-Tablante, et al. WHO. Breastfeeding and COVID-19. Scientific Brief. 23 June 2020. https://www.who.int/publications/i/item/10665332639.
Chambers et al. Evaluation for SARS-CoV-2 in breast milk from 18 infected women. JAMA. 2020
Cosma et al. The “scar” of a pandemic: cumulative incidence of COVID-19 during the first trimester of pregnancy. J Med Virol. 2021
Fell et al. Risk of preterm birth, small for gestational age at birth,a dn stillbirth after COVID-19 vaccination during pregnancy: population based retrospective cohort study. BMJ. 2022
Goldshtein et al. Association of BNT162b2 COVID-19 vaccination during pregnancy with neonatal and early infant outcomes. JAMA Ped. 2022
Hcini et al. Maternal, fetal and neonatal outcomes of large series of SARS-CoV-2 positive pregnancies in peripartum period: a single-center prospective comparative study. Eur J of Obstet Gynecol. 2021
Hamidi et al. Adverse perinatal outcomes in pregnancies affected by severe COVID-19 infection. ACOG. 2022
Hernandez-Diaz et al. First trimester COVID-19 and the risk of major congenital malformations-international registry of coronavirus exposure in pregnancy. Birth Defects Res. 2022
Hoyert, D.L. Maternal Mortality Rates in the United States. Health E-Stat. 23 February 2022. Available online: (accessed on 5 May 2022).
Hui et al. Reducations in stillbirths and preterm birth in COVID-19 vaccinated women: a multi-center cohort study of vaccination uptake and perinatal outcomes. AM J Obstet Gynecol. 2022
Kachlikis et al. Analysis of vaccine reactions after COVID-19 vaccine booster doses among pregnant and lactating individuals. JAMA Network Open. 2022
Kalafat et al. SARS-CoV-2 vaccination in pregnancy: a unique opportunity for equity. Lancet. 2021
Kharbanda, et al. Spontaneous abortion following COVID-19 vaccination during pregnancy. JAMA. 2021
Kharbanda et al COVID-19 Booster Vaccination in early pregnancy and surveillance for spontaneous abortion. JAMA Network Open. 2023
Kiefer, M.K.; Mehl, R.; Costantine, M.M.; Johnson, A.; Cohen, J.; Summerfield, T.L.; Landon, M.B.; Rood, K.M.; Venkatesh, K.K. Characteristics and perceptions associated with COVID-19 vaccination hesitancy among pregnant and postpartum individuals: A cross-sectional study. BJOG. 2022
Kugelman et al. JAMA Pediatr. 2021
Levy et al. Acceptance of COVID-19 vaccination in pregnancy: a survey study. AJOG. 2021
Lipkind et al. Receipt of COVID-19 vaccine during pregnancy and preterm or small for gestational age at birth – eight integrated health care organizations, United States, December 15,2020-July 22,2021, MMWR. 2022
Magnus et al. COVID-19 vaccination during pregnancy and first trimester miscarriage. NEJM. 2021
Malderelli et al. Remdesivir treatment for severe COVID-19 in third –trimester pregnancy: case report and management discussion. Open Forum ID. 2020
Mangat et al. BNT162b2 vaccination during pregnancy protects both the mother and infant: anti-SARS-CoV2 S antibodies persistently positive in an infant at 6 months of age. Case Rep on Pediatr. 2021
Mullins et al. Pregnancy and neonatal outcomes of COVID-19: The PAN-COVID study. Eur J Obstet Gymecol Reprod Biol. 2022
Muyldermans et al. The effeects of COVID-19 vaccination on lactating women: a systematic review of the literature. Front Immunol. 2022
Paul and Chad. Newborn antibodies to SARS-CoV-2 detected in cord blood after maternal vaccination: a case report. BMC Pediatr. 2021
Peng et al. A study of breastfeeding practices, SARS Co-V-2 and its antibodies in the breast milk of mothers confirmed with COVID-19. Lancet. 2020
Perl et al. SARS-CoV-2 specific antibodies in breast milk. JAMA. 2021
Prabhu et al. Antibody response to coronavirus disease 2019 (COVID 19) messenger rna vaccination in pregnant women and transplacental passage into cord blood. Obstet Gynecol. Aug 2021.
Rottenstreich et al. Timing of SARs-Co-V-2 vaccination during the third trimester of pregnancy and transplacental antibody transfer. Clin Micriobiol and Infect. 2021
Shimabukuro et al. Preliminary findings of mRNA covid-19 vaccine safety in pregnant persons. NEJM. 2021
Smith et al. Clinical risk factors of adverse outcomes among women with COVID-19 in the pregnancy and postpartum period: a sequential,prospective meta-analysis. Am J Obstet Gynecol. 2023
Thoma, M.E.; Declercq, E.R. All-Cause Maternal Mortality in the US Before vs During the COVID-19 Pandemic. JAMA Netw. Open 2022, 6, e2219133.
Zauche et al. Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion. NEJM. 2021.
ACOG: https://www.acog.org/clinical-information/physician-faqs/covid-19-faqs-for-ob-gyns-obstetrics
MotherToBaby: https://mothertobaby.org//?s=covid
CDC: https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-with-medical-conditions.html
COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 (COVID-19) Treatment Guidelines. National Institutes of Health. Accessed 4.27.2023
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