Nifedipine in Pregnancy – Uses and Side Effects

Nifedipine is one of the most effective drugs to prevent unwanted early labour. If you are heading towards preterm labour for unexplained reasons, then chances are your doctor will put you on nifedipine. However, before taking this drug, first, you need to understand its use and side effects. It may work like magic for many pregnant women, but the same may not hold true for you. Moreover, it may not be suitable for you due to its side effects, so consult with your doctor before taking this medicine. This article explores the applications of nifedipine in pregnancy, its benefits, the conditions it treats, and the possible adverse effects, providing a comprehensive understanding of its role in prenatal care.

What Is Nifedipine?

Nifedipine is an anti-contraction medicine. It slows down uterine contractions, which in turn delays preterm labour. It is also a calcium channel blocker, which helps treat medical conditions like high blood pressure and heart disease.

Is Nifedipine Safe for Pregnant Women?

Nifedipine can be safe for pregnant women when prescribed by a doctor, especially in the second and third trimesters. It is often used to treat preterm labour and hypertension. However, it should be used under medical supervision to monitor for potential risks to the mother and fetus (1).

How Does Nifedipine Work During Pregnancy?

Nifedipine slows down the contractions in the uterus since it’s a calcium channel blocker, and the uterus requires calcium to contract. Nifedipine obstructs the pathways, preventing calcium from reaching the uterus. So, you must be wondering how it helps delay labour, right? Nifedipine blocks the calcium and allows the uterus and other soft tissues in one’s body to relax, which delays labour (2).

When Is Nifedipine Used During Pregnancy?

Typically, your doctor will put you on nifedipine if you are susceptible to unexplained preterm labour. The following cases usually lead to the prescription of nifedipine by your doctor:

• If you are diagnosed with thinning of the cervix, and if your cervix dilates to 4 cm way earlier than your due date (6).
• A rupture of membranes, even while the mother’s amniotic sac is intact.
• Unexpected labour, even though the foetus is not in distress and still has time until the due date.
• When other uterus contraction-preventing medicines, such as terbutaline (Beta- Sympathetic medicine), prove to be ineffective.
• If the intake of other drugs has ceased, consider the unwanted side effects.
• If there is a need to delay the labour for 24 to 48 hours to treat other underlying conditions, such as corticosteroid treatment (this is done to treat the lungs of the foetus).

How Much Nifedipine Should Be Taken During Pregnancy?

The dosage and administration of nifedipine while pregnant depend on the condition being treated and the specific needs of the patient. The typical dosage for nifedipine in the context of preterm labour starts with an initial loading dose of 20 mg, which can be followed by another 20 mg after 30 minutes if contractions continue. Maintenance doses usually involve 10-20 mg orally every 6-8 hours (5).

Side Effects of Nifedipine During Pregnancy

Although nifedipine works wonders for most women by delaying preterm labour, it has a few side effects, like many other medicines. Usually, it is believed to inflict no damage or side effects on the mother or her child, except in severe medical cases. Following are some of the common side effects of taking nifedipine during pregnancy (3):

• Headaches
• Constipation
• Nausea
• Dizziness
• Low blood pressure
• Red skin rashes
• Diarrhoea
• Hot or warm flashes
• Heart palpitations (4)
• Feeling faint

Tips for Pregnant Women

It is always recommended to avoid any unnecessary medication, especially if it is something that your doctor does not prescribe. Following are some tips for you to have a better understanding:

• It is highly unlikely for your doctor to prescribe this medicine unless you experience a sudden case of preterm labour. Moreover, in any other situation, this medicine will not be used at any point during your pregnancy.
• Pregnancy is a delicate phase. Ensure you follow your doctor’s advice and take your medications on time.
• Nifedipine and other such medicines are prescribed only in extreme cases.
• If there is a possibility of using nifedipine during preterm labour, then it’s always better to discuss it in detail with your gynaecologist to rule out any odds.
• Pregnancy requires the utmost level of care to ensure the safety of the mother and child. If you are expected to have preterm labour for reasons other than medical, then it becomes even more crucial for you to pay attention to your health and well-being.
• To analyse your condition carefully, your doctor also requires your correct medical history. So, always be honest when communicating your medical history to your doctor.

When to Call a Doctor?

During pregnancy, you will experience a multitude of changes in your body. However, understanding those changes and their timings is crucial to rule out any odd event. Usually, a normal pregnancy lasts for about 40 weeks. However, if one’s labour starts during the 37th week or before that, then it may prove harmful to both the mother and child. Hence, it is advisable to seek medical attention as early as possible. Following are some symptoms indicating that you need to visit a doctor at the earliest:

1. Frequent contractions
2. Lower abdominal pressure
3. Vaginal spotting or bleeding
4. Pelvic pressure
5. Vaginal discharge
6. Diarrhoea
7. Water breaking

FAQs

1. Can nifedipine be used in all trimesters of pregnancy?

Nifedipine is most commonly used in the second and third trimesters. Its use in the first trimester is less common due to limited data on its safety during early fetal development. The decision to use nifedipine during any trimester should be based on a thorough risk-benefit analysis by a healthcare provider.

2. What should I do if I miss a dose of nifedipine during pregnancy?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. Do not take a double dose to make up for the missed one. It’s essential to keep your healthcare provider informed about any missed doses.

3. Are there any dietary restrictions while taking nifedipine during pregnancy?

While taking nifedipine, it is generally advised to avoid grapefruit and grapefruit juice, as they can interfere with the medication’s metabolism, potentially leading to increased side effects. A balanced diet and regular prenatal vitamins are recommended, but always consult a healthcare provider for personalised dietary advice (7).

Consult your doctor immediately if you experience any of the given symptoms or other issues. It’s always better to address a problem at its earlier stage to ensure the safety and well-being of the mother and her child. It is also recommended that you consult with your doctor before taking any medication, especially if it’s a drug like nifedipine, which is used only in case of an emergency.

References/Resources:

1. PROCARDIA XL; The US Food and Drug Administration; https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/019684s023lbl.pdf

2. PROTOCOL: Tocolysis with Nifedipine; Cree Health; https://www.creehealth.org/sites/default/files/nifedipineprotocol_revised_March6%2C2007.CMDPaproved.pdf

3. Childress. C. H, Katz. V. L; Nifedipine and its indications in obstetrics and gynecology; PubMed; https://pubmed.ncbi.nlm.nih.gov/8134077/#

4. Nandita. M, Vincent. C. K, Va. D; Maternal and fetal cardiovascular side effects of nifedipine and ritodrine used as tocolytics; The Journal of Obstetrics and Gynecology of India; https://www.semanticscholar.org/paper/Maternal-and-fetal-cardiovascular-side-effects-of-Nandita-Vincent/920097c7705c4811494d762a1e5d6c692bd107d7

5. Gáspár. R, Hajagos-Tóth. J; Calcium channel blockers as tocolytics: principles of their actions, adverse effects and therapeutic combinations; PubMed Central; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816733/

6. Songthamwat. S, Na. Nan. C, Songthamwat. M; Effectiveness of nifedipine in threatened preterm labor: a randomized trial; PubMed Central; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007202/

7. Grapefruit and medication: A cautionary note; Harvard Health Publishing; https://www.health.harvard.edu/staying-healthy/grapefruit-and-medication-a-cautionary-note; March 2021

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