Number and Rate of Positive COVID-19 Cases in ...

The rate of COVID-19 in pregnant women, by maternal age and month, in Scotland. Based on COPS pregnancy database updated in mid-September 2021, and cases of COVID-19 with date of onset up to 31 August 2021.

Maternal age is the age of the woman at the estimated date of conception.

For any individual, the specimen date of their first positive viral PCR result is taken as the date of onset of their first episode of COVID-19.
Subsequent positive viral PCR results with specimen date within 90 days of their first positive result are discounted.
If the individual then has a positive viral PCR result with specimen date ≥90 days after their first positive result, this is taken as the date of onset of their second episode of COVID-19.
Subsequent positive viral PCR results with specimen date within 90 days of this second index date are then discounted as for the first episode of COVID, and so on. COVID-19 is defined as occurring in pregnancy if the date of onset for any episode of infection occurs at any point from the estimated date of conception (date the woman was 2+0 weeks gestation) up to and including the date the pregnancy ended.

Looking at the totals for all months combined, if a woman has two pregnancies during the period covered, with different maternal age group (due to passing a birthday) assigned to the separate pregnancies she will be counted against the total for each relevant age group, but only once in the overall (all ages) total. This means that the overall (all ages) total may be slightly lower than the sum of the specific age groups totals.