From the Guidelines
Lactulose is a recommended and effective treatment for constipation during pregnancy, particularly when dietary modifications and bulk-forming laxatives are insufficient. According to the most recent guidelines from 2024, osmotic laxatives like lactulose can be safely administered during pregnancy 1. Constipation affects 20%–40% of pregnant individuals, and lactulose works by drawing water into the intestines, softening stool, and promoting bowel movements.
The typical dosage of lactulose is 15-30 ml once or twice daily, which can be adjusted based on response. Most pregnant women see results within 24-48 hours of starting treatment. Lactulose is minimally absorbed systemically, making it a safer option during pregnancy compared to stimulant laxatives 1. However, excessive use of lactulose can cause maternal bloating, and stimulant laxatives should be avoided due to conflicting safety data.
Key considerations for treating constipation during pregnancy include:
- Increasing dietary fiber intake to the recommended daily amount of approximately 30 g/d
- Consuming an adequate amount of fluids, particularly water, to help soften stools and ease bowel movements
- Using bulk-forming agents like psyllium husk or methylcellulose, which are safe to administer in pregnancy due to the lack of systemic absorption
- Avoiding straining during bowel movements by providing ample time, using relaxation techniques, and adjusting diet and hydration 1.
It is essential to consult with a healthcare provider before starting any medication during pregnancy to ensure it's appropriate for your specific situation.
From the FDA Drug Label
Pregnancy Teratogenic Effects Pregnancy category B. Reproduction studies have been performed in mice, rats, and rabbits at doses up to 2 or 4 times the usual human oral dose and have revealed no evidence of impaired fertility or harm to the fetus due to lactulose. There are, however, no adequate and well-controlled studies in pregnant women Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Lactulose is not explicitly recommended for treating constipation during pregnancy in the provided drug label. Although it is classified as Pregnancy category B, indicating that animal reproduction studies have shown no evidence of harm to the fetus, there are no adequate and well-controlled studies in pregnant women. Therefore, lactulose should be used during pregnancy only if clearly needed 2. Its effectiveness for constipation in pregnant women is not directly addressed in the label.
From the Research
Effectiveness of Lactulose for Constipation during Pregnancy
- Lactulose is an osmotic laxative that is commonly used to treat constipation during pregnancy 3, 4.
- A study published in 1995 found that lactulose was effective in increasing the frequency of defecation and normalizing stool consistency in pregnant women with constipation 3.
- Another study published in 2020 compared the safety and efficacy of polyethylene glycol 4000 and lactulose for the treatment of constipation in pregnant women, and found that both treatments were effective, but polyethylene glycol 4000 had a faster therapeutic effect than lactulose 5.
- A review of interventions for treating constipation in pregnancy published in 2015 found that there was insufficient evidence to comprehensively assess the effectiveness and safety of lactulose, but suggested that it may be a useful treatment option 6.
Safety of Lactulose during Pregnancy
- Lactulose is not absorbed in the small intestine, which makes it a safe treatment option for constipation during pregnancy, as it does not pose a risk to the fetus 3, 4.
- A study published in 2016 found that lactulose was safe and effective for the treatment of postpartum constipation, with no significant changes in vital signs or adverse events reported 7.
- The US Food and Drug Administration (FDA) has classified lactulose as a category B drug, which means that it is considered safe for use during pregnancy, although the evidence is limited 4.
Recommendations for Use
- Lactulose is recommended as a first-line treatment for chronic constipation during pregnancy, along with macrogol (polyethylene glycol) 4.
- The dosage and duration of treatment with lactulose should be individualized based on the patient's response and medical history 3, 7.
- Patients should be monitored for adverse events and changes in bowel habits, and the treatment should be adjusted as needed 5, 6.