If I Get Pregnant in September, When Am I Due?

Due dates for a September 2027 conception

A pregnancy lasts about 266 days (38 weeks) from conception, so a September conception leads to a due date in May or June. The table gives the estimated due date for each possible conception day, and the date a home pregnancy test is usually reliable — about two weeks after conception, around when the next period would be due.

Dates for 2027. In other years the due date is the same or one day different, depending on leap years.

An autumn conception: what it means for you

Conceiving in September leads to a due date in late May or June. Your first trimester overlaps the busy end of the year, when tiredness and nausea can clash with celebrations — it is fine to rest. A summer baby arrives in long, light days, but late pregnancy in early summer heat calls for plenty of fluids and shade.

Seasons and timing

With conception in September, the first trimester runs until about November, the second trimester covers the months after, and the third trimester begins around March. In the northern hemisphere, that puts the last weeks of pregnancy in spring and the birth in spring (the seasons are reversed in the southern hemisphere). Spring’s milder weather often makes the final weeks more comfortable, though pollen can make hay fever worse for some.

Because most babies arrive between 37 and 42 weeks, a baby conceived in September could be born in the month before or after the due month. Your baby’s birthday is most likely to fall between May 3, 2028 and Jul 6, 2028.

Conception dates are estimates

Few people know the exact day they conceived. Conception happens within about a day of ovulation, which can be up to five days after sex. If you know the first day of your last period, the Due Date Calculator is the standard method. For any month at a glance, see the Conception Due Date Chart.