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Morning Sickness: The low down on Nausea and Vomiting in Pregnancy!

early pregnancy pregnancy pregnancy symptoms May 06, 2020



Nausea and vomiting of pregnancy (NVP), which usually starts between 5 and 12 weeks of pregnancy, is quite common; up to 80% of pregnant women experience nausea and vomiting at some point in their pregnancies and between 3-6% of pregnant women experience severe nausea and vomiting, which we commonly refer to as hyperemesis gravidarum. The symptoms usually peak around 9 weeks and typically improve by weeks 16 to 18 of pregnancy. Unfortunately for some women these symptoms actually persist through pregnancy (up to 20% of women have symptoms until the third trimester and for 5% of women their symptoms persist until delivery) But just because it’s common doesn’t mean it’s something that women just have to deal with, in fact, it’s quite the opposite. 


Nausea and vomiting in pregnancy can significantly impact your quality of life, your mental health; it can increase anxiety and worry about how it’s affecting the fetus, how it’s affecting your ability to work and can also impact your relationships. 


Why do women get nausea and vomiting in pregnancy? 

Believe it or not...the cause of nausea and vomiting in pregnancy is not entirely understood! Hormonal changes are thought to play a significant role, including elevated levels of estrogen, though the rising levels of bHCG, human chorionic gonadotropin, which peaks in the first trimester is thought to significantly contribute to the symptoms as well. 

Additional theories include abnormal gastric motility, meaning your stomach may empty more slowly than usual. What’s really interesting is that it’s not just the hormonal or gastric changes that occur, but how your body responds to these changes that makes some women more likely to experience nausea and vomiting. Genetics (including family history or personal history) is often thought to play a role, so if your siblings or mother had NVP, there is a good chance you may experience it as well. 


Why do we want you to tell us about it? 

We want to help. Even if your symptoms are mild, we’ve got many tips and tricks (that we’ll get to soon) to help you manage your symptoms. 

Also, because nausea and vomiting of pregnancy ‘aka morning sickness’, is what we call a diagnosis of exclusion. What this means is that we, as your care providers, need to make sure that there is nothing else going on causing your symptoms. Just because you’re pregnant, doesn’t mean that we are going to simply brush off symptoms.

We need to review your symptoms and ensure that we’re not concerned there could be something else at play contributing to how you are feeling, like thyroid abnormalities, side effects of another medication or substance use (marijuana can sometimes be thought of as a treatment for nausea and vomiting, and we’ll talk more about cannabis use in another episode, but chronic use can actually be an underlying cause for nausea and vomiting).

Additional things we need to exclude include infection, underlying eating disorder (like anorexia or bulemia) and several other less common causes like migraines and other more rare hormonal causes. 

How do we diagnose it? 

Typically it’s diagnosed by process of elimination. It must onset in the first trimester and we must exclude other possible causes of your symptoms (as described above). If your symptoms start after the first trimester, then we’d be more suspicious that something else may be going on causing you to have nausea and vomiting. 

Why do we want to initiate treatment early?

The reason we want to initiate treatment early is to help YOU get your symptoms under control as early as possible. If we start treating early, it is possible that we may prevent more serious complications like dehydration, weight loss, and the need for hospitalization. 

Additionally, if we delay treatment until your symptoms are severe and you’re experiencing complications it can become more difficult to get those symptoms under control. 

What treatment options do we have? 

We break treatment options down into two categories non-pharmacological (i.e not medication) and pharmacological (medications). 


  • Dietary changes: 
    • Eating before or as soon as you feel hungry to avoid an empty stomach
    • Often times having a small snack on your bedside table to have before getting out of bed can be helpful for women who’s nausea is worse first thing in the morning
    • Some women find protein more tolerable than fats and carbohydrates
    • Eat smaller meals, and more slowly as usual to event an overly full stomach which can worsen nausea
    • Avoid lying down right after meals
    • Try to drink your water between meals, again to minimize the effect of an overly full stomach and avoid drinking fluids during meals if possible
    • Fluids best tolerated include cold, clear, and carbonated or sour (eg, ginger ale, lemonade, popsicles) and taken in small amounts
    • Try sniffing fresh lemons, drinking lemonade or eat slices of watermelon
  • Avoiding triggers
    • Everyone’s triggers are going to be different, but some common triggers include stuffy rooms, odors (eg, perfume, chemicals, food, smoke), heat, humidity, noise, and visual or physical motion (eg, flickering lights, driving), excessive exercise, excessive fatigue, foods/snacks high in sugar, spicy foods, high fat foods 
  • Fatigue can worsen NVP and we know that sleep requirements also increase in early pregnancy; we as health care providers have a liberal approach towards recommending increased rest and leave-of-absence from work to support women through NVP
  • Brushing teeth after a meal, spitting out saliva, and frequently washing out the mouth can also be helpful. 
  • Switching to a different toothpaste may help women for whom strong mint-flavored toothpaste is a trigger.
  • Supplements containing iron should be avoided until symptoms resolve as iron causes gastric irritation and can provoke nausea and vomiting
  • Some women may find chewable prenatal vitamins more tolerable than tablets or capsules. If prenatal vitamins are stopped, a supplement containing folic acid (400 to 800 mcg daily) is recommended until prenatal vitamins are again tolerated - you can also take a kids chewable with your folic acid. 
  • Ginger is something that many women find helpful for nausea in the form of ginger ale, ginger tea, ginger tablets or even candied ginger 
    • (eg, ginger lollipops, ginger tea, foods or drinks containing ginger root or syrup)
    • However, if prescribed, a common dose is 1 to 1.5 g orally divided over 24 hours (eg, 250 mg ginger capsules orally four times a day). In a 2014 systematic review and meta-analysis of 12 randomized trials (n = 1278 pregnant women), ginger improved nausea compared with placebo but did not significantly reduce vomiting 
  • Acupressure and acupuncture treatments help some women with NVP;
    • ~ 30% of women find these treatments can relieve symptoms at the P6 acupressure point (The point is found three of the patient's finger breadths above the wrist in between the two tendons)
    • Sea-Band acupressure bracelets can be helpful as well as they stimulate the same acupressure point on your forearm 
  • Practice mindfulness! A study looked at Vit B6 alone vs. Vit B6 and mindfulness based CBT and tho small, found MBCT helped women reduce NVP symptoms as well as improved symptoms of anxiety and depression.

Please DO NOT use marijuana, THC or CBD products. They have NOT been shown to be safe in pregnancy and are NOT recommended for treatment. Additionally, long-term marijuana use and withdrawal can actually increase nausea and vomiting. 


If the above mentioned strategies aren’t cutting it, which is the case for many women in early pregnancy, we often turn to medications that can reduce symptoms and improve quality of life. 

Vitamin B6 - Vit B6, also referred to as pyroxidine, is a water soluble vitamin and has an excellent safety profile and given that it’s a vitamin many women are comfortable starting here.  As a single agent, the recommended dose of pyridoxine is 10 to 25 mg orally every six to eight hours; the maximum treatment dose suggested for pregnant women is 200 mg/day. Studies have shown that it can be effective at improving mild to moderate nausea, but doesn’t really reduce vomiting. 

Our next go to, if Vit B6 alone isn’t effective at controlling nausea, is the combination of Doxylamine succinate and pyridoxine (in Canada this is a well known product referred to by it’s trade name Diclectin;  Diclegis and Bonjesta in the United States). Doxylamine is a first generation antihistamine, and pyridoxine, as we just learned, is Vitamin B6. 

Doxylamine-pyridoxine  as a combination treatment appears to be more effective than either drug alone and it’s safety has been well established in pregnancy.

Initially, we prescribe two extended-release tablets (each tablet contains doxylamine 10 mg and pyridoxine 10 mg) at bedtime. The dose may be increased to four tablets over the course of the day, as needed, for more severe nausea (one tablet in the morning, one tablet in the midafternoon, two tablets at bedtime).  Important to note that this medication is more for prevention than for treatment.  So if your nausea is worse in the morning, take it before bed.  If worse in the afternoon, take in the get the gist!


If lifestyle and dietary changes in combination with doxylamine/pyriodoxine is ineffective at managing your nausea then we typically look at medications targeted to more severe symptoms. 

The next step after Diclectin is often dimenhydrinate (commonly referred to in Canada by it’s trade name Gravol). It can be taken orally and also rectally every 4-6 hours. We also often give this intravenously in hospital for women who are admitted with severe NVP (hyperemesis). 

If dimenhydrinate isn’t able to get your NVP under control the next medication we often turn to is metoclopramide (Maxeran). These are dopamine antagonists that aid in stimulating gastric motility and emptying your stomach. This can be taken by mouth, or additionally can be given through an intravenous or intramuscular (shot in the leg/arm) up to 3-4 times/day. We have excellent data available that reassures us that this is safe in pregnancy.

If you’ve tried a combination of at least two of the above medications with little to no improvement in your NPV, we often then turn to ondansetron (zofran). 

You may have heard some controversy in this medication in pregnancy due to the possible small increase risk in cleft palate and cardiac anomalies in babies born to mothers who used this drug in the first trimester of pregnancy. Currently it’s listed as a pregnancy category B medication, which means there is no evidence of risk in studies, but this has not been confirmed in controlled studies in women in the first trimester. 

In addition to the above, we will often recommend trialing acid-reducing medications as these combined with anti-nausea medications can often offer a significant improvement in symptoms. Medications commonly used include ranitidine, or esomeprazole. 

If you are experiencing severe NVP, which we refer to as hyperemesis, you will likely need to be admitted to hospital for initiation of your management. Hyperemesis typically presents with women who have persistent vomiting associated with weight loss, low blood pressure and often laboratory abnormalities (electrolytes). 

Women are often most concerned not with their symptoms but how the NVP is affecting the fetus. Fear not, there is no increase in fetal malformations of infants born to mothers with NVP or hyperemesis, regardless of what medications they did or didn’t take. There is often no difference in birth weight or gestational age at time of birth for women who were affected by NVP/hyperemesis compared to those that weren’t as long as they had a normal pre-pregnancy weight and they had appropriate weight gain later in pregnancy. 

So, you’re pregnant now and you’re wondering when you should seek help? Generally we’d recommend seeking help in the following situations: 

  • Your symptoms are new and you want reassurance and review of how to manage
  • Your symptoms were previously manageable with non-pharmacological approaches but are worsening and you want to discuss next steps
  • You are showing signs of dehydration (infrequent urination, dark urine, ++ dizziness with standing)
  • Excessive vomiting throughout the day
  • Blood with vomiting
  • Abdominal or pelvic pain or cramping
  • Unable to keep any food or fluids down for > 12 hours
  • Weight loss of > 5 pounds (2.3 kg)
  • Fever/diarrhea in association to NV
  • Feelings of hopelessness, wanting to end pregnancy etc. 


Another question is, is this likely to happen in subsequent pregnancies, and unfortunately the answer is yes. So is there anything you can do to prevent it next time around? 

Well making sure you’re taking a prenatal vitamin with folic acid at least 1 month prior to conception can reduce the risk of fetal malformation and may decrease the frequency and severity of NVP. B-complex vitamins taken pre-conception and early pregnancy may also reduce NVP. Additionally if you have heartburn or acid reflux pre=pregnancy getting these symptoms under control before you get pregnant may reduce the severity of symptoms while pregnant. And if we know you’re at high risk, consider starting doxylamine/pyridoxine at the onset of pregnancy to try to prevent your symptoms from snowballing out of control!

Take home points:

  • If you’re experiencing NVP, you can d/c your iron-containing PNV during T1 and substitute with folic acid or chewable vitamins low in iron; Iron requirements do NOT increase in T1 so unless you have iron deficiency, it’s safe to avoid Iron as it can often worsen NVP
  • Eat WHATEVER pregnancy-safe food that appeals to you! There is no evidence that short-term diatery deficiencies during early pregnancy will have any long-term consequences on your pregnancy 
  • Don’t hesitate to give GINGER a try
  • Acupressure may be helpful…and if you’re symptoms are mild and you’re wanting to avoid medications you may want to invest in a pair of SeaBands
  • If you’re into CBT, give it a go! There is definitely no harm and lots of potential benefits beyond improving your nausea





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