My wife’s scan says 6w5d, but we married later. Is it likely?

Question

Hello doctor,

I recently got married, and now my wife is pregnant. We went for an ultrasound, and the report shows that the baby is six weeks and five days old. I am concerned because the baby's age appears to be more than the time that has passed since our marriage.

Can this happen?

Please advise.

Answer 1

Hello,

Welcome to icliniq.com.

I understand your concern.

Thank you for sharing the ultrasound image and related details (attachments removed to protect the patient’s identity).

Based on the ultrasound report, your wife's pregnancy is measured at six weeks and five days. This is consistent with a last menstrual period (LMP) that occurred a few days before your wedding, which aligns with the information you provided.

Let me explain how this works. Pregnancy age is calculated from the first day of the last menstrual period (LMP), not from the date of conception or intercourse. So, even if intercourse occurred for the first time on your wedding night, the pregnancy would still be dated from the LMP, which typically occurs about two weeks before ovulation and conception.

Therefore, a gestational age of six weeks and five days at the time of the ultrasound is completely accurate if her LMP occurred shortly before your marriage. This means the baby is not older than your marriage. This method of dating is standard and expected.

Ultrasound dating in early pregnancy is very accurate, usually within a few days, and relies on LMP unless there is a significant discrepancy. So there is no need to worry, the pregnancy likely began after your marriage.

I hope this helps.

Thank you.