(Closed) Low BMI and getting pregnant

posted 5 years ago in Pregnancy
Post # 2
2092 posts
Buzzing bee

It’s been pretty much proven that BMI is not a good indication of health level, because it doesn’t take into account body types or muscle mass or family history. 

If you are healthy otherwise, I wouldn’t worry about what your BMI

Post # 3
7435 posts
Busy Beekeeper
  • Wedding: February 2013

I would think that as long as you are having regular cycles, it shouldn’t be a problem.

Post # 5
692 posts
Busy bee
  • Wedding: March 2013

I know a girl who is naturally skinny as well, and skinnier than you actually. She had a healthy baby boy : )

She had snack a bit more than her usual and she chose nutrient dense foods (like almonds). Just make sure you eat enough to sustain your baby and you’ll be fine.

Post # 6
2054 posts
Buzzing bee
  • Wedding: May 2013

The concern with having a low bmi and TTC is you may not have enough body fat for your body to think it can support a baby so you might not ovulate/have periods.  But if you are having regular cycles when you are off the pill you should be fine TTC! good luck to you!!

Post # 7
11747 posts
Sugar Beekeeper
  • Wedding: November 1999

Firemansgirl:  I’m 5’4 95-100 lbs and got pregnant in one shot. As long as you’re healthy otherwise and ovulate regularly you will be just fine I’m sure! My docs were never concerned and I only gained 20lbs during pregnancy and lost it within 1-2 weeks. Good luck! 


Post # 8
2815 posts
Sugar bee
  • Wedding: June 2012

If you’re having regular cycles, I would say there’s probably not a whole lot to worry about. You body can just naturally function properly at a low weight, and that’s ok!

I would just make sure you’re taking prenatals beforehand, and try to eat as healthy as possible. Taking a good DHA supplement when TTC and while pregnant won’t hurt either.


Good luck!

Post # 9
5000 posts
Bee Keeper
  • Wedding: September 2013

Do you exercise? If you don’t exercise a lot, really truly eat enough, and you’re getting normal periods, I would guess that your weight would not be an issue. The most common reason people with low BMIs can’t get pregnant is because they don’t eat enough (even if they eat “a lot,” they may be exercising it off). 

Post # 10
1141 posts
Bumble bee
  • Wedding: January 2010

I am 5’3″ and weighed just about 100 lbs before pregnancy. I’ve never had regular periods (unless I was on the pill). When I went off the pill, my periods were crazy, I had a total of 4 over 9 months before I got pregnant. I went to my OB and he ran tests and did an ultrasound and said everything looked normal, but my low BMI was probably messing up my cycle. He suggested charting to see if I was ovulating. The first month charting, I got pregnant (turns out I ovulated on CD 24!). I had a healthy pregnancy, gained 20 lbs, had a 6 lb 3 oz healthy boy, and lost all of the baby weight within 2 weeks.

Good luck!!

Post # 11
1724 posts
Bumble bee
  • Wedding: March 1998

The people telling you that if you have a cycle and it seems normal, you’re likely OK, have not painted the whole picture. While it’s LIKELY that you are still ovulating normally, many women only discover after fruitlessly trying for months that they are not (different issue, but there are still many women with PCOS who have normal cycles). I’d suggest temping/using OPKs for a few months to get a better look at whether or not you’re ovulating; if all of the cycles appear normal, you’re probably fine. If one or more are off (i.e., you’re not getting temp shifts or you do not get positive ovulation tests), it could be that putting on weight or seeing a doctor could be the right move for you.


Low BMIs (even slightly low) tend to have a much more drastic impact on fertility than being slightly or moderately overweight (even slightly into the obesity category). While it’s possible that you have enough body fat, given the 2.5 point difference away from a “normal” BMI, it may be less likely (let’s also keep in mind that certain ethnic groups follow different BMI categories — i.e., people of Asian descent tend to have higher body fat levels at lower weights, though this usually applies to the upper end of categories. I.e., if you’re classed as underweight, that’s a universal label across ethnic groups — usually below levels of 18.5)

In the same shoes, I would probably talk to a doctor more at length about the possible implications on fertility — because you are considered a minimum of 10 pounds underweight. Many doctors simply go by appearance, or they aren’t that well-versed in what’s considered underweight (but know what’s overweight). Keeping silent on it does not necessarily mean that it could not be an issue for you later on.


Post # 12
70 posts
Worker bee


Firemansgirl:  I’m 5′-6″ and 104 lbs… I’m 10 weeks pregnant, and got pregnant right away. I’m also 33, so at 24 you should have an edge 😉 Good luck!

Post # 13
70 posts
Worker bee

I should add to my comment that I concur with PPs that body type factors in. I have a low BMI, but I also have a very small frame, so I’m by no means skin and bones. I’ve never had a doctor tell me to gain weight. Very low body fat is a problem, but BMI is not a good measure of body fat because it doesn’t reflect body type.

Post # 15
437 posts
Helper bee

Firemansgirl:  As long as your eating enough to give your baby the nutrients it needs it should be fine. Generally woman who have a lower bmi are recommended to put on more weight throughout their pregnancy

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