SARS-CoV-2 in First Trimester Pregnancy

A Cohort Study

N. la Cour Freiesleben; P. Egerup; K.V.R. Hviid; E.R. Severinsen; A.M. Kolte; D. Westergaard; L. Fich Olsen; L. Prætorius; A. Zedeler; A.-M.H. Christiansen; J.R. Nielsen; D. Bang; S. Berntsen; J. Ollé-López; A. Ingham; J. Bello-Rodríguez; D.M. Storm; J. Ethelberg-Findsen; E.R. Hoffmann; C. Wilken-Jensen; F.S. Jørgensen; H. Westh; H.L. Jørgensen; H.S. Nielsen


Hum Reprod. 2021;36(1):40-47. 

In This Article


A total of 1356 double tests were performed from 1356 pregnant women during the study period. Of the 1356 women, 1019 (75.1%) provided informed consent to participate (Cohort 1). Additionally, 36 women with an early pregnancy loss prior to the time of the double test were included (Cohort 2). The overview of the study is illustrated in Figure 1.

Figure 1.

Flowchart of the two cohorts.

The median gestational age was 11 weeks and 0 days (11 + 0) at the double test and 13 + 0 at first trimester scan. The median gestational age among the 36 women with early pregnancy loss was 8 + 1. The characteristics of the two cohorts are presented in Table I.

The total number of women with SARS-CoV-2 antibodies (positive IgM and IgG values or IgG-only) in Cohort 1 was 18 (1.8%). Two women were IgM and IgG positive, and 16 women were IgG-only positive. Eight women in Cohort 1 were IgM-only positive (IgM values 8.3–15.1 AU/ml). Five of these had a follow-up blood sample 54–77 days after the double test sample, and none developed IgG ≥10.0 AU/ml. None of the 36 women from Cohort 2 had SARS-CoV-2 antibodies.

For Cohort 1, we subsequently compared the nuchal translucency thickness (measured at the first trimester scan) between women with SARS-CoV-2 antibodies reflecting previous infection versus no previous infection. Women, where the fetus was found to have a chromosome anomaly (trisomy), were excluded from the analysis of the nuchal translucency thickness. The median nuchal translucency thickness, free β-hCG and PAPP-A levels as well as the MoM values were not significantly different between women with versus without SARS-CoV-2 antibodies (Table II). Also, after accounting for maternal age and gestational week, positive antibodies (P = 0.81) did not affect nuchal translucency thickness.

Table III displays pregnancy status for all 1055 pregnancies (1019 in Cohort 1 and 36 in Cohort 2) after the first trimester and according to SARS-CoV-2 antibodies. For the 1019 pregnancies in Cohort 1, 15 women had a pregnancy loss between the double test and the nuchal translucency scan, 3 women were diagnosed with a missed abortion at the nuchal translucency scan (Figure 1) and 1 woman was lost to follow-up after the double test. One woman with SARS-CoV-2 antibodies had a pregnancy loss and 17 women with ongoing pregnancies had SARS-CoV-2 antibodies. There was no significantly increased risk of pregnancy loss in women with antibodies (OR = 3.4, 0.08–24.3 95% CI, P = 0.27).

Figure 2 illustrates COVID-19 symptoms reported by pregnant women with negative or positive SARS-CoV-2 antibodies. Significantly more women with antibodies reported COVID-19 symptoms in early pregnancy compared to women without antibodies (53% versus 26%) (OR = 3.2, 95% CI 1.1–9.6, P = 0.023). One woman with antibodies did not answer the questionnaire regarding symptoms of COVID-19. Among the 9 (53%) women with SARS-CoV-2 antibodies who reported symptoms of COVID-19 in early pregnancy four women reported only one symptom and five women reported two or more symptoms. Reported symptoms were: Ageusia and or anosmia (n = 5), dry cough (n = 4), extreme tiredness (n = 3), fever (n = 2), arthralgia (n = 2), dyspnea (shortness of breath) (n = 2) and headache (n = 1).

Figure 2.

Incidence of self-reported coronavirus disease 2019 (COVID-19) symptoms for women with and without Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in first trimester pregnancy.

The cumulative frequency of pregnant women included after the double test (Cohort 1) and with SARS-CoV-2 antibodies during the study period is displayed in Supplementary Figure S1.

Supplementary Figure S1.

The cumulative frequency of pregnant women with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antibodies during the study period.