Is Weighing Necessary During Pregnancy?

A while ago, we discussed whether routine weighing at medical appointments is really necessary. 

I reminded people that if weighing bothers them, is triggering to them, or is just against their principles, then routine weighing can be opted out of because you have the right to informed refusal of any test or procedure.  I also reminded people of the times when weighing can be medically necessary versus when it's simply a matter of routine policy, and that the two should be differentiated.

But what about weighing during pregnancy?  Is it really necessary to weigh a pregnant woman at each visit?

Unfortunately, this question is not as simple to answer.  You can make a case both for and against routine weighing at every prenatal appointment.

For the most part, though, the question is moot, because most care providers require weighing at each appointment. You can question its necessity all you want, but most providers are going to require it.

If you are a woman of size who wants to bear children but prefers not to be weighed, the sad truth is that you are either going to have to:

• find a way to make peace with the weighing requirement, or
• be prepared to go outside traditional attendants to find those who are more flexible about routine weighings

Weighing = Standard of Care?

Among OBs in the USA, prenatal weighing at every appointment is considered standard-of-care.  If an OB were to not weigh a woman regularly and she later had a problem and sued, that OB could have his/her feet held to the fire in court for not weighing her. 

So, beneficial or not, for most care providers, the "standard of care" argument trumps all the other arguments against routine weighings.  It is simply what is expected medically and legally.

However, it's not "standard of care" in all countries to weigh.  Some doctors in other countries do not weigh pregnant patients at all, even fat ones. Others do not weigh average-sized patients, but will weigh patients regularly who weigh outside the "norm" --- that is, very thin or very fat patients. 

Midwives vary more in whether or not they weigh clients.  Many midwives (especially the ones in hospitals who practice with OB colleagues) do weigh women regularly, but not all do.  I have heard from several hospital midwives in other countries who do not regularly weigh their clients, and I have heard from others that do.  Much depends on the standard of care in that area, and whether or not the midwife practices within the medical model or not. 

Many homebirth midwives here in the USA and abroad do weigh patients routinely, but will let you opt out of it if you prefer.  I found a midwife like this for my fourth pregnancy. (Bless her heart forever). 

But basically, in the U.S., unless you are interested in the homebirth route and have a very flexible midwife, you are almost surely going to be weighed at each prenatal appointment. 

So what are the pros and cons of weighing pregnant women?  Why do it or not do it?

Arguments For and Against Weighing During Pregnancy

There are a variety of reasons providers give for weighing during pregnancy.  Some of them are very legitimate concerns, and some are more dubious.

Monitoring Pregnancy Weight Gain

The reason most commonly given for weighing routinely in pregnancy (and the reason I find least compelling) is to be sure patients don't gain outside the weight gain recommendations.

The main problem with this is that what is considered the "proper" weight gain in pregnancy changes over time. In the 50s, 60s, and 70s, women were told to strictly limit weight gain, to the point that many babies were being born underweight or premature. So then the weight gain guidelines changed, encouraging more weight gain to try and lessen these complications (which they did).

Recently, the more generous weight gain guidelines have been challenged, with many researchers contending that women gain too much weight now, putting themselves at increased risk for a "too-big" baby, a higher rate of cesareans, or retaining too much of the weight after the pregnancy is over. 

Both of these arguments have data to back them up. There is some research that suggests that really large gains are harmful in pregnancy, resulting in extra-big babies and more long-term obesity in the mother.  And there is definitely research that shows that a too-small gain is associated with prematurity and/or too-small babies, even in "obese" women. 

So obviously, a happy medium is the ideal.  But what is considered the "optimal weight gain" is still under debate.  Currently, the latest recommendations from the Institute of Medicine (IOM) are: 25-35 lbs. for "normal" weight women, 28-40 lbs. for "underweight" women, 15-25 lbs. for "overweight" women, and 11-20 lbs. for "obese" women. 

So while what is considered the "correct" weight gain is trendy and changes over time, you could certainly make a case that preventing the extremes of weight gain (too low or too high) might prevent complications, or catch them early enough to intercede. 

On the other hand, weight gain doesn't give much reliable information about a woman's actual nutrition or general health.  Some women have a gain within "normal" limits, yet do so eating mostly junk food.  Some women gain "too much," yet have perfectly good nutrition.  Weight gain as a proxy for a woman's nutritional intake and health is a shaky concept at best.

Furthermore, weight gain doesn't correlate all that well with outcome either.  Some women gain a large amount in pregnancy, yet have perfectly healthy babies and great outcomes.  Some gain less than optimally, yet the outcomes are still good.  Some women gain within the guidelines and have poor outcomes. Pinning too much importance on weight gain amounts is not a reliable indicator of outcome.

Personally, I think far too much importance is placed on the numbers on the scale instead of on the actual nutrition and habits of the woman.  The medical community relies on weight gain as a marker for appropriate nutrition and predictor of outcome, and I think these associations are weak at best. 

However, given the very short appointments most OBs have with patients and the difficulty this can lead to in knowing how a woman is eating, I can understand them wanting some way to monitor the pregnancy's progress.  Not all women are truthful about their nutrition to their providers, and a too-high gain or a too-small gain could be an early warning of someone who is having difficulties managing their food intake.  It could be a marker for the need to intercede early, so I can understand a provider's wish to weigh patients on that level.

Still, isn't the better option the midwifery model of care, which takes more time in each appointment so the care provider knows the client better and understands her particular needs and concerns? 

The midwifery model is the one that takes the time to really emphasize proactive care (including good nutrition) in preventing many complications. It takes time to thoroughly go over general nutritional principles in pregnancy, and it tailors nutritional advice to each woman's individual needs.

While some midwives do weigh their clients routinely to watch for any alarming trends, most de-emphasize the scale in favor of emphasizing the importance of excellent, proactive nutrition and exercise.  To me, emphasizing nutrition seems far more important to me than how much weight a woman actually gains (or not) in pregnancy. 

Most of the time, routine weighings to monitor weight gain as a surrogate for monitoring nutrition or predicting outcome is a weak argument at best, and  besides, judgments of the what is the "proper" amount of weight gain tend to change over time. 

In my opinion, a better approach is to emphasize excellent nutrition and regular exercise and trust the woman's body to gain the amount it needs.

Monitoring Fetal Growth

Another reason many  providers like to weigh women regularly in pregnancy is to monitor fetal growth closely.  As noted, research shows a too-large gain may predict a big baby, and a too-small gain may predict a premature or underweight baby, both of which are associated with risks.

Really large gains can be associated with macrosomia (big baby), and this raises the specter of shoulder dystocia (where the shoulders get stuck).  Although most of the time this is resolved without problems, sometimes this can cause damage to the baby, to the mother, or in rare cases, result in the death of the baby. It is one common reason for lawsuits in obstetrics, which is why doctors worry about it so much.

However, weight gain is only moderately associated with macrsomia. Many women gain average amounts in pregnancy and yet still have "big" babies.  Some people gain a lot in pregnancy and have average-sized babies. Some of us (me!) gain almost nothing in pregnancy and still have big babies.

I am dubious of the idea that weight gain is a really reliable marker for discovering macrosomic babies.  I think research does show that a really high gain increases the number of macrosomic babies but taking a large gain as a guarantee of a big baby amd acting in fear accordingly may cause more problems than it solves.

In fact, monitoring weight gain can backfire because a large gain often triggers an early induction or a planned cesarean for a "big" baby, only some of whom will actually be big, and many of whom will have poorer outcomes because of the interventions.

Research clearly shows that these interventions do not improve outcome and often worsen it, regardless of the size of the baby.....so monitoring weight gain closely and planning interventions based on large gains may actually cause more harm than good in many cases.

On the other hand, weight gain can be a good marker for small-for-gestational-age (SGA) babies.  Research consistently shows that poor weight gain in pregnancy is associated with SGA and/or premature babies.  A very low rate of weight gain, especially in a woman who is already on the thin side, is a marker for strong concern and could be considered a good reason to weigh pregnant women regularly.

However, in "obese" women, the relationship between weight gain and fetal size is more tenuous. Many of us do not gain much weight at all in pregnancy (or even lose a little) and yet still have babies of average or large size.

Yet it's important to remember that even in "obese" women, there is a relationship between low weight gain and SGA/premature babies. It's not as strong a relationship as in smaller women, but it is there.  This is one of the reasons why the push for very little or no weight gain in "obese" women is troubling.

So you could make a case that a woman of size who is not gaining much should have fetal size monitored, just in case.  Chances are that everything is fine in a woman of size with low gain, but it might be helpful to check baby's growth curve periodically, since SGA babies tend to be at higher risk for stillbirth and prematurity.

However, weight is not the only way to monitor fetal growth; measuring the height of the top of the uterus (fundal height) is pretty universal among care providers.  If a problem is suspected via fundal height, then more close supervision of the mother's weight gain might be appropriate, along with other measures of fetal growth. 

Estimating fetal size by ultrasound is also an option.  It's not that accurate at predicting a too-big or too-small baby, but it does fairly well in identifying babies that are average-for-gestational-age.  In other words, it has difficulty accurately identifying all the babies at the extremes of growth, but it's better at ruling out extremes of growth for many babies and reassure everyone that all is well.  This is not a perfect solution, but it is another option.

The argument for weighing women to monitor fetal growth is one that has some merit, but it also carries risks as well as benefits.  If a large gain is used as a marker for more intervention, chances are the risks will outweigh the benefits.  However, if it is used selectively, and particularly to watch for women with too-small babies, the benefits may outweigh the risks.

Pre-Eclampsia

Another major reason for weighing in pregnancy is that a sudden large gain can be a potential symptom of Pre-Eclampsia (PE). In PE, fluid retention is common, and one of the first clues to PE can be a sudden jump in weight gain.

Because PE is a very serious complication of pregnancy and a potential killer, this is one logical reason for monitoring weight gain closely in pregnancy.

The problem with this is that women don't gain weight uniformly each week in pregnancy. Some weeks there are bigger gains, some weeks there is very little gain. Unless there's a huge jump, a bigger gain one week does not necessarily indicate pre-eclampsia.

Yet most doctors measure gains on a diagonal line of "average" gain per week, and some overreact to any deviation from this average...especially in women of size. Realistic providers understand that gain is not always even week to week, yet it's unfortunately very common for women to be hassled about even a small gain above the average "permissable" gain.

While a really big, sudden weight gain jump can be used as a marker to indicate possible PE, even a small gain is often over-reacted to in women of size. Many providers believe that all fat women will develop PE, so they are quick to react to any gain above what they think "should" be taking place. Combine that with the lack of consistency about using a larger blood-pressure cuff in women of size, and many providers are quick to diagnose PE in fat women when there may or may not actually be a problem.

Routine weighing can be advantageous in that it may be one of the first signs that PE is developing, but it also often results in major interventions and hassles, particularly for women of size.

Iatrogenic Harms

What many providers fail to realize is that while regular weighings in pregnancy can sometimes spot complications early on and prevent them from becoming worse, they can also result in unneeded intervention and harm.

In many providers' eyes, a woman with a large prenatal weight gain is a cesarean waiting to happen. They assume that a large gain means a big baby, and so they are more likely to induce labor, do a planned cesarean before labor, or have a very low threshold for proceeding to a cesarean during labor because they are afraid of shoulder dystocia.

In fact research shows that a larger weight gain is associated with a higher risk for cesarean, even when the baby is not big.  Is this because something physical about the bigger weight gain prevents vaginal birth, or is it more about the provider's fear levels and anticipation of trouble?  I think there is a strong case to be made for the latter.

This is one of the problems with monitoring a pregnant women's weight gain closely.  Too often, it's not just neutral information, designed to prevent complications, but instead becomes loaded information used against the woman to instigate interventions at the slightest provocation. 

Are the majority of interventions used around weight gain monitoring really justified?  Do they truly improve outcomes?  Or do many of the interventions put into effect when a woman has a gain outside the norm cause more harm than good?

This is the question that researchers are not examining closely enough.  The medical model is good at helping the small amount of women who truly need assistance during pregnancy, but it is typically very poor at recognizing and changing its own physician-caused (iatrogenic) harms. 

And monitoring weight gain so closely that the care provider freaks out over every little ounce is a very common iatrogenic harm these days.

What If You Prefer Not To Be Weighed In Pregnancy?

Weighing women in pregnancy at every visit is the standard of care in the U.S.A. and in many other countries as well.  Even those places that don't weigh most women may want to weigh women of size regularly in the belief that this might prevent complications (or catch them early). 

Therefore, if you are a person who finds weighing triggering or have a strong philosophical objection to weighing, it can be difficult to find a birth attendant who will honor that objection.

Women of size who wish to avoid regular weighings should look into an alternative-style birth attendant, like a homebirth midwife or a birth center midwife. Although most of these care providers also weigh regularly, they are less likely to be adamant about it and may be willing to work out a compromise position.

Make questions about regular weighings part of your interview process when trying to find a provider.  Share honestly with them the reasons that you prefer not to weigh, and ask them frankly whether or not they could be comfortable avoiding the scale.  Offer to weigh yourself each week and keep track of your own gain, and to let them know if you see a big jump in gain or loss at any point, or if your gain is too low or extremely high overall.  

Reassure them that you care very much about your nutrition, offer to keep food diaries to reassure them that you are getting good nutrition, and note that you will be open to nutrition counseling as needed if it's non-judgmental and reasonable.

Some midwives who normally weigh will be comfortable with avoiding weighing under these conditions.  They just need reassurance that they will be told if there are any disturbing trends in weight gain, and that your nutrition will be consistently good. 

Some midwives will never be comfortable omitting weight gain in prenatal appointments, and in that situation you will have to decide just how important it is to you (or not) to avoid prenatal weighings.

Handling Weighings If Your Care Provider Insists On Them

If you have chosen a high-tech birth attendant who insists on weigh-ins and it bothers you to be weighed, you do have some options. 

Many women find it easier to endure weighings if they take control of the process themselves.  Some choose to turn their backs while being weighed.  Others request that the med tech weigh them without comment and write down the numbers without saying them out loud.

You can share your concerns about regular weighings with the care provider and ask them to let you have some control over the process, or at least to be careful about the kind of comments they make to you about weight gain.

At no time should you ever put up with shaming body talk or critical comments about your results.  Providers who indulge in that kind of talk will not be size-friendly during the birth process and are likely to see you as a disaster waiting to happen.  If you hear negative or shaming comments when weighing or about your weight gain, it's time to find a new provider.

Or you can do what I do when there is a medically-necessary weighing; I don't passively let someone else weigh me, but instead I tell them I can do it myself and they can watch to verify it. I move the scale to about the right number (so there's no long process of over- or under-estimating and adjusting), and I adjust the balance until it's correct.  Somehow it's not so bad or quite so threatening if I do it for myself. 

Sometimes I get a med tech who is very threatened by the idea of me weighing myself (I think they assume I must be trying to fudge the number), but most of the time they are fine with watching me do it.

Mind you, I still hate being weighed by strangers....it reminds me of all those diet program weigh-ins, all the judgment that went with those, and all the living and dying emotionally based on what the scale was doing...but I find it less offensive if I am the one in control of the process. And I never let them make comments about the results.

This was how I handled being weighed in my first 3 pregnancies.  Although I refuse routine weighings when not pregnant, I didn't realize there was any choice when pregnant and so I went along with the weighings the first 3 times.  It wasn't too bad.

Since I'm okay with what I weigh, check myself regularly at home, and don't have an eating disorder (some people with eating disorderes find weighing to be a trigger), I could make peace with the idea of weighing in order to rule out pre-elcampsia or a too-small baby.....but I can't say I ever enjoyed the process.  I just gritted my teeth and got through it. 

Best by far, though, was finding providers who did not require that I be weighed during pregnancy. In my fourth pregnancy, I found birth attendants who were okay with me opting out of weighing. They knew me well enough to realize that they could trust my nutrition and they knew I kept track of my own weight and would report any big gains or losses, and any pre-eclampsia symptoms.

So they were completely fine with me not weighing at ALL in the whole pregnancy, and I have to say, that was SOOOO incredibly freeing! What a breath of fresh air.

They may never realize what a gift they gave me by letting me opt out of that, but blessings on them forever for being flexible that way.

Conclusion

Weighing during pregnancy has many pros and cons. 

On the plus side, it can catch some cases of inadequate weight gain that may lead to a higher risk for a premature or too-small baby, or it may catch an incipient case of pre-eclampsia before it gets too serious.  A too-large gain, caught early, may allow intervention to improve nutrition and perhaps prevent some cases of macrosomia. 

On the minus side, weight gain measurement is often used against women (and especially women of size), leading to more interventions and risky procedures like inductions and cesareans.  Furthermore, it is a poor surrogate for predicting nutritional adequacy or pregnancy outcome. 

A more sensible approach would be to emphasize nutrition over weight gain.  Alas, in today's short appointments, meaningful nutritional counseling is difficult to do and weight gain becomes the stand-in measurement of nutritional adequacy. 

Therefore, to most U.S. maternity care providers, weighing during pregnancy is an absolute requirement. If you have decided to go with a typical OB or hospital midwifery practice, you will almost surely be weighed at every appointment. Find a way to deal with that process proactively so it's not bothersome to you. 

Beware the care provider who is highly restrictive, shaming, or overly-interventive based on your weigh-in results.  That is a classic sign of weight bias and will likely lead to a highly-interventive and high-risk birth.  Better to switch providers than have to put up with that kind of bias during pregnancy.

And if you really object to being weighed during pregnancy, remember that there are some birth attendants who do not require regular weigh-ins. If it's something that really bothers you, you might want to check out one of these providers and see just how freeing it can be.

*I'm interested in hearing YOUR experiences, in or outside the U.S.A.  Where are you from? Do care providers usually weigh women in pregnancy in your area?  Why or why not?  Do they weigh women of size more?  Do they recommend restrictive policies or use shaming comments? Do you think weighing was helpful or hurtful in your case?  How did you feel about being weighed?

If you are a provider, I'm interested in hearing about your reasons for weighing or not weighing, how you monitor nutritional adequacy, and if you weigh, how you help women through an experience many women (of all sizes!) find nerve-wracking.