COVID-19 and Pregnancy: Early Research Provides Critical Answers

COVID-19 and Pregnancy: Early Research Provides Critical Answers

Do you know someone who is pregnant? This information may be useful.

Dr. Christina Chambers’ area of research focuses on pregnancy and lactation in reproductive-aged women, and provides critical information on viral infections and outcomes for women and child. She was part of the panel of speakers at the January Howell Webinar ‘Top Ten Health Stories in Women’s Health, 2020 Edition’, where experts spoke about current research efforts that made an impact on women’s health.

Dr. Chambers is the Program Director of MotherToBaby California. She is a world‐renowned perinatal epidemiologist and a Professor of Pediatrics and Family and Preventive Medicine at the University of California San Diego. Her interests are in the areas of birth defects and other pregnancy outcomes, with a special focus on exposures that can cause birth defects. Dr. Chambers is also the lead investigator for the organization’s pregnancy research, a series of observational studies that examine the effects of medications, vaccines, and diseases during pregnancy.

Pregnant and lactating women are the most understudied group in women’s health research. The uncertainties of a viral disease and the secondary effects of potential drug treatments during pregnancy make it difficult to identify how unborn developing babies and newborns can react to illness and drug treatment.

For her, the top one story of 2020 was about COVID-19 in women during pregnancy and lactation, and how it affects newborns. “There are many viruses that a person can be infected with during pregnancy that are known to increase the risk of harm for the developing baby. So when a new virus comes along, there’s immediately interest in whether or not it might have an impact on pregnancy, the developing baby and the newborn.”

Dr. Chambers covered the most pressing and frequently asked questions regarding COVID and the health of women through pregnancy, and the outcomes for the developing baby and newborns. The research she presented addressed:

  • Pregnancy and the risks and outcomes in pregnant and lactating women.
  • Virus transmissibility from mother to child during pregnancy and lactation
  • Health disparities and its effect in pregnant women
  • Vaccination during pregnancy

Are pregnant women more likely to get infected? Are they more likely to have severe outcomes from COVID-19?

A study between January and October of 2020 looked into the effects of COVID-19 on women of reproductive age, specifically 461,000 who had marked a pregnancy status.  Per information from the CDC Case Report Surveillance Study:

  • Pregnant women did not appear to be more likely to be diagnosed with symptomatic disease.
  • Among those with symptomatic disease, pregnant women didn’t appear to be at a higher risk to be diagnosed with COVID-19 because of the pregnancy.
  • However, pregnant women, if infected with COVID, were three times more likely than non-pregnant women to be admitted to the ICU – 2.9 times more likely to be put on a ventilator and 1.5 times or 50% more likely to die.
  • These risks were particularly high in Asian and native Hawaiian, Pacific Islanders.

Can the mother transmit the virus to the baby during pregnancy?

Dr. Chambers presented relevant research taking place that addresses neonatal COVID-19 transmission. Although studies have shown a slim risk of post-natal infection, some report possible intrauterine transmission. SARS-CoV-2 antibodies were detected after birth in some infants, especially where it was thought that they could not have gotten it postnatally.

As for maternal outcomes in pregnant women diagnosed with COVID 19, she indicated that preterm birth rates due to COVID complications fluctuated between six to 10% of pregnancies. In a systematic review of 30 reports, results showed a 17% preterm birth rate – two to three times higher than expected. However, when assessing the number of women who had a planned delivery by C-section or induced labor, the preterm birthrate dropped substantially to 6%. Studies continue on preterm births.

A small study from a health system in Pennsylvania analyzed the maternal and neonatal cord blood of 83 infants born to COVID infected mothers. The study found that SARS-CoV-2 was found in 2/3 of the infants, suggesting that antibody levels tend to be higher when the mother was infected during the early stage of pregnancy- rather than later.

“Antibodies may protect the baby from future infection. The results of the research support the benefit of earlier vaccination in pregnancy, whether it be by intrauterine transmission or vaccination.”

Health disparities, pregnancy and COVID.

As expected, infection was less likely in women in higher socio-economical levels, indicating health disparities play a major role: “Infection was more likely in women living in neighborhoods with high unemployment rates, neighborhoods with large household membership and neighborhoods with greater household crowding. In terms of race/ethnicity and insurance coverage, Hispanic women seem to be disproportionately represented among those infected”, comments Chambers.

Lactation: Breast milk is safe.

Aside from exposure, major concerns among lactating women revolved around the fear of infection through breastfeeding, including for new mothers that depended on donor milk supply: when do antibodies appear in the mom? To what extent are the antibodies present in the breast milk? Can continued breastfeeding by a previously infected mom protect the baby from infection over the longer term?

In March 2020, and in collaboration with the Pandemic Infectious Disease group at UCLA, Dr. Chambers’ research shed important data for infected, lactating women to take into consideration in two critical areas:

  • An analysis of viral RNA in a small sample of donated breast milk, which was spiked with the SARS-CoV-2 virus, showed that there was no evidence that the milk itself could infect the baby, suggesting that infection via breast feeding was little to non-existent.
  • The pasteurization of donated breast milk seemed to take care of destroying the virus.


Dr. Chambers is currently leading research efforts addressing the effects of the vaccine in pregnant and lactating women. The study has several women enrolled, who have received one or both doses of the two vaccines, evenly distributed across the first, second and third trimester.

Given all the preliminary research results on virus transmissibility via pregnancy and lactation, the presence of antibodies in the mother’s milk, and the higher risks of negative outcomes for women who get diagnosed with COVID-19 during pregnancy, Dr. Chambers agrees with the American College of Obstetrics and Gynecology and its recommendation that the vaccine should not be withheld from pregnant and lactating women who meet the criteria for vaccination.

“There is no reason to suspect there are any increased risks that would outweigh the benefits of vaccination in pregnant women.”

Clearing misconceptions with reliable, science-based research results.

The MotherToBaby program, which is a US-wide organization, provides counseling services for pregnant and lactating women, including information about potential and harmful exposures. The organization also conducts nationwide pregnancy outcome and lactation research studies. Between March of 2020 and February 2021, the program had enrolled over 1000 women who are now participating in research studies, and registration continues to grow.

Clinical data from these studies are helping set the standards in the way the healthcare system can take care of pregnant/ lactating women and infants, and importantly, provide science-based information to the mother to make an informed decision about her health and that of her child.

This list of additional resources provides the latest updates on COVID, pregnancy, lactation and vaccination.


About the Howell Foundation:

The Howell Foundation advances women’s health by funding undergraduate and graduate research scholarshipsawarding grants to scientists who conduct research benefiting under represented women in the community, and supporting outreach efforts and events that promote health education and self-advocacy for the long-term health and well-being of women, their families and the community in which they live.

Photo by Neal E. Johnson

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