Expert: Catherine Beier MS CBE - 9/25/2009

Question
Hi Catherine, Just giving you an update on a previous question on paternity. The due dates from the original early US have changed a couple of times since I last wrote and by quite a bit. Her original due date was Nov. 4th, she went for an US two weeks ago with her midwive and they told her it is actually due on October 27th then just yesterday she had another US done and they said the baby was was actually 36 weeks and 3 days old and changed her due date to Oct.18th. What does all this mean? which one is the correct one if any? I thought if anything they would've told her she wasn't as far along as we thought and changed her due date to a later date making me more plausible at being the father since I didn't have sex with her again until Feb. 22nd. How would they know this late into it that the baby is 36 weeks and 3 days old when I thought US done this late are very inaccurate? That would make her est. conception date about Jan. 25th I believe, and she told me she had her period on Jan. 30th so how could it be possible that she conceived on Jan. 25th and still have her period? Also, on a side note does pregnancy cause small clusters of white bumps to form around the anus? I saw her looking up genital warts online the same day she came back from her doctors visit and thought it a little odd then I remembered the white bumps I saw a few weeks ago and wondered if she was looking this up out of curiosity for someomone else or if she was told something at the doctors.

Answer
Mark,


The early ultrasound is the most accurate.  What they're probably really saying is that the baby is measuring large for dates and will probably come sooner than later due to its accelerated growth rate.  This can be due to genetics, diet, and other hereditary factors, not because the initial dates were wrong.


This does not mean that their estimates are accurate, either.  Late ultrasound can be off by 2 weeks in either direction, meaning unless the dates are more than 2 weeks apart, the due date shouldn't be changed.


The real question is why so many ultrasounds.  Unless she's having problems, then they're not necessary and can cause more harm than good because they become so inaccurate.  The American College of Obstetricians & Gynecologists doesn't even recommend that an ultrasound needs to be done at all in pregnancy, unless complications arise.


Now, to answer your next question, no it's not common for white bumps to form during pregnancy.  It sounds like there may be something else she's not telling you.



Best,
Catherine