Causes for a tendency to go post term?

[Franfierce]

Hi ladies
Does anyone know if any causes have been identified for going post term? I’ve been trying to read up on it and it seems things like delays in implantation and pregnancy hormone growth can be indicators for it. I’ve also heard it can be genetic. Does anyone have any personal experience or other knowledge of this?

I went overdue (41.6 according to obgyn, 41.1 by my own count), baby and I were doing well with no cervical changes yet, but Obgyn insisted on induction so I wouldn’t “kill my baby” who was also apparently “too big if we wait” :-/ the induction failed, I only got to 2cm dilation and baby ended up in distress, so off we went to a CS. DD came out weighing 3.7kg and according to pediatrician she didn’t look overdue. I myself weighed 4.1kg at birth (42 weeks) and hubby was 4.6kg at term (oh lord!) so she certainly wasn’t big for someone with our gene pool.

I’m TTC now and doing everything to avoid the way it happened last time. My body and DD clearly weren’t ready last time and I’m worried I’ll go overdue again and will be under pressure to do an induction or elcs.

Back in the 80s my mum went overdue with her first two babies and ended up with CS. For my youngest brother she had a scheduled CS at 39 weeks and he ended up in intensive care because his lungs weren’t ready so it makes me wonder whether in my family we just gestate longer and need to go to 41-43 weeks. Do certain ethnicities have longer pregnancies?

Any thoughts, experiences, links to research, arguments to present to my obgyn would be very very appreciated. A bit nervous about this already! Thank you!!

No experience personally as currently pregnant with my first to go beyond 12 weeks. However, I have a friend who had her first at 42+1, her second at 42+4 and her 3rd was a c section at 41+3 due to transverse lie. With all 3 her placenta was still functioning well and looked good post delivery and none of the babies had the appearance of being significantly overdue. On the reverse my brother’s oldest was also born at 42+4 (hospital told her she was behind her dates on scan measurements and baby was small - baby came out and she’s her skin like a snake, placenta was beginning to look ‘failing’ according to the midwife; plus she weighed 9 1/2lb so far from small for dates!!)

Hopefully others will come along with some research articles or more personal experiences however, so long as everything appears to be going ok and you and baby are monitored regularly, you can refuse induction if it’s based on dates only.

Some babies go a bit longer because biology is an inexact pseudoscience. (Jokes - physicists are forever making fun of biology. Check my username...).

If you found a nice warm cave and you were warm and fed and happy, would you leave unless you had to? Babies are born when they are outgrowing their 'cave' or when the 'cave' environment becomes unsuitable in another way for them. This happens for a variety or reasons and depends on the baby and the person. Genes may or may not play a part...

Also scans are inexact as are most people's dates. For example, I was born nearly three weeks 'over', my sister was born two weeks 'over'. My sister ovulated late in her cycle but they induced her at 10 days 'over' (even though she might not have been) when she had her daughter. I had an ivf pregnancy and my dd was born at 40.5. So we know my dates exactly. Still 'over'.

Interestingly, you're considered overdue at different dates depending on country. In France, term is 41 weeks, for example.