Medicines used in pregnancy
On this page you will find information and resources on prescribing in pregnancy
Medicines in Pregnancy, Children and Lactation
Information on the use of medicines in human pregnancy is generally lacking, especially for new or infrequently used products.
Bumps is provided by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by Public Health England on behalf of the UK Health Departments. UKTIS answers enquiries from health professionals (e.g. doctors, nurses, midwives) on the effects on the unborn baby of medicines and other chemicals that the mother may use or otherwise be exposed to. Somerset NHS Foundation Trust have produced printable leaflets. Choice and Medication© leaflets are designed to help service users, carers and family members understand their medicines better, and to make more informed decisions, best as part of a discussion with a healthcare professional.
Please see the Traffic Light System for categorisation of individual drugs which defines where responsibility for prescribing between primary and specialist clinicians should lie.
Please expand the topics below for more detailed information.
UK Teratology Information Service (UKTIS) provides various maternal exposure abstracts openly available as well as paternal exposure abstracts. Healthcare professionals can contact the service Monday to Friday.
Best Use of Medicines in Pregnancy (Bumps) is provided by the UKTIS, various patient information leaflets are available suitable for the public, useful for all.
Specialist Pharmacy Service SPS has published significant resources on many areas of prescribing in pregnancy, including the prescribing in pregnancy and safety in pregnancy- training and treatment resources in pregnancy
For comprehensive advice and training materials Safety in Pregnancy – Specialist Pharmacy Service (SPS) has resources on:
Questions to ask when giving advice on medicines in pregnancy
Information resources that give advice about medicines in pregnancy
Assessing risk and informing the risk versus benefit decision for medicines in pregnancy
The principles of prescribing in pregnancy
Royal College of Gynaecologists (RCOG) Green-top Guideline No.69 The Management of Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum. Also see formulary guidance below under Nausea and Vomiting.
Electronic Medicines Compendium (EMC) – Individual drug data sheets, contain information published by manufacturers.
Somerset NHS Foundation Trust have commissioned – Choice and Medication© leaflets which are designed to help service users, carers and family members understand their medicines better, and to make more informed decisions, best as part of a discussion with a healthcare professional.
Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review MHRA January 2021 update.
Allergic rhinitis in pregnancy access information from Specialist Pharmacy Service for safety and first line choices in pregnancy – Hayfever or allergic rhinitis: treatment during pregnancy
Specialist Pharmacy Service – Asthma: treatment during pregnancy
NHS Somerset Respiratory webpage
Formulary Chapter 3: Respiratory system
Specialist Pharmacy Service – Constipation: treatment during pregnancy
Specialist Pharmacy Service – Diabetes: treatment during pregnancy
The MHRA published a report in March 2022 showing no safety concerns with the use of metformin in pregnancy.
NICE Clinical Knowledge Summary: Management of Dyspepsia in pregnancy
Self-care first line:
Patient information link: NHS Indigestion and heartburn in pregnancy
- Eat smaller meals more frequently (every 3 hours), do not eat late at night (or less than 3 hours before bedtime), and avoid known irritants (for example alcohol, caffeine, fruit juices and carbonated drinks, chocolate, and fatty and spicy foods). Keep a food diary to identify triggers.
- Try raising the head of their bed by 10–15 cm.
- Avoid medications that may cause or worsen symptoms, if appropriate (for example calcium-channel antagonists, antidepressants, and nonsteroidal anti-inflammatory drugs).
- Stop smoking (if applicable).
Antacids and alginates are recommended as first-line treatments if symptoms are relatively mild and are not controlled adequately by lifestyle changes suitable for self-care.
If symptoms are severe, or persist despite treatment with an antacid or alginate, consider prescribing an acid-suppressing drug.
UKTIS: Use Of Proton Pump Inhibitors In Pregnancy
Specialist Pharmacy Service: Heartburn and Dyspepsia: treatment during pregnancy
Update on MHRA review into safe use of valproate – Update on MHRA review into safe use of valproate 12/12/22:
The CHM has advised that no one under the age of 55 should be initiated on valproate unless two specialists independently consider and document that there is no other effective or tolerated treatment. Where possible, existing patients should be switched to another treatment unless two specialists independently consider and document that there is no other effective or tolerated treatment or the risks do not apply.
Valproate use by women and girls MHRA updated guidance 11/02/2021 – Information about the risks of taking valproate medicines during pregnancy.
2022/23 Community Pharmacy Contractual Framework National Clinical Audit – Reducing the potential for harm from valproate prescribing in patients of childbearing age who are biologically able to be pregnant.
Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review MHRA January 2021 update.
Valproate use by women and girls March 2018 MHRA update on Information about the risks of taking valproate medicines during pregnancy.
General Medical Council: Discussing the risk of sodium valproate this case study developed by the GMC with the General Pharmaceutical Council and the Nursing and Midwifery Council highlights the risk of harm created by taking sodium valproate during pregnancy.
The Epilepsy medicines and pregnancy leaflet above, aims to help support patients in understanding the risks for epilepsy medicines in pregnancy. It contains important information, including do not stop taking epilepsy medicines until you have talked to your specialist, GP or epilepsy specialist nurse.
Specialist Pharmacy Service: Epilepsy: treatment during pregnancy signposts evidence based information on the treatment of epilepsy in pregnancy.
NHS Somerset formulary Contraception page
NHS Somerset formulary Mental Health page
Refer to the Somerset Traffic Lights System Document located on this page for details on individual drugs
Chapter 4.2 Epilepsy and other seizure disorders formulary page
Folic acid should be taken by all women and people assigned female at birth who may become pregnant to reduce the risk of having a baby with a neural tube defect.
Usually folic acid 400 micrograms daily should be started 3 months before pregnancy (where possible) and continued throughout the first 12 weeks of pregnancy, this is available over the counter and suitable for self-care.
NICE Public Health Guideline [PH11] advise that GPs should prescribe 5mg of folic acid a day for women and people assigned female at birth who are planning a pregnancy (3 months before conception where possible), or are in the early stages of pregnancy, continuing for the first 12 weeks if they:
- (or their partner) have a neural tube defect
- have had a previous pregnancy with a neural tube defect
- (or their partner) have a family history of neural tube defects
- have diabetes type 1 or 2
- have epilepsy Epilepsy in Pregnancy Green-top guideline No. 69 RCOG or take anti-epilepsy medication
- have a BMI 30kg/m2 or greater RCOG Green-top Guideline No.72
- Individuals taking sulfasalazine
- Individuals treated with low dose methotrexate (≤25mg/ week) within one month prior to conception.
- Individuals treated with low dose methotrexate at time of conception, note- these individuals should be advised to stop methotrexate immediately and referred to their specialist for urgent review.
GP’s should also prescribe for people who may become pregnant/ planning pregnancy ideally 3 months prior to conception and throughout the entire pregnancy for:
- Individuals with sickle cell disease, thalassaemia or thalassaemia trait
Herbal medicines: safety during pregnancy information shared from the SPS
Hypertension in pregnancy NICE Quality Standard and guidance.
Pregnant people at increased risk of pre-eclampsia at the booking appointment are offered a prescription of 75–150 mg of aspirin to take daily from 12 weeks until birth. NICE Quality statement 2.
GPs should prescribe 75-150mg of aspirin (unless contra-indicated) from twelve weeks of pregnancy until birth for people with one high risk factor, or more than one moderate risk factor for pre-eclampsia.
High risk factors include:
- hypertensive disease in a previous pregnancy
- chronic kidney disease
- autoimmune disease, such as systemic lupus erythematosus or antiphospholipid syndrome
- type 1 or type 2 diabetes
- chronic hypertension.
Moderate risk factors include:
- first pregnancy
- age 40 years or older
- pregnancy interval of more than 10 years
- body mass index (BMI) of 35 kg/m2 or more at first visit
- family history of pre-eclampsia
- multi-fetal pregnancy.
Hypertension in pregnancy: diagnosis and management Visual Summaries
- planning care for women at moderate and high risk of pre-eclampsia
- assessment of proteinuria and care plans
- chronic hypertension: pre-pregnancy advice
- chronic hypertension: antenatal care
- gestational hypertension: antenatal care
- intrapartum care and place of care
- criteria for choice of critical care level (hypertension, pre-eclampsia and eclampsia)
- follow-up care and postnatal review
- antihypertensive treatment during the postnatal period
- risk of long-term cardiovascular disease
- pre-eclampsia: antenatal care
- risk of recurrence of hypertensive disorders of pregnancy
Specialist Pharmacy Service: Hypertension: treatment during pregnancy
See our Shared Care and Patient Group Directions webpage for patient information leaflets on ‘Taking aspirin to reduce the risk of pre-eclampsia’, available in two different formats for printing purposes, for patients accessing the community pharmacy PGD. Includes the use of aspirin in patients who have low levels of placental protein (Low PAPP-A) identified by blood tests taken at the 11-14 week scan screening, as well as people with sickle cell disease.
The NHS website has some useful information on becoming a parent and discusses testosterone and fertility.
People assigned female at birth (AFAB) can become pregnant while taking testosterone if they do not use contraception.
Somerset’s Fertility Policy can be accessed through the Evidence Based Interventions Service page, under policies and applications.
Acute care toolkit 15. Managing acute medical problems in pregnancy Nov 2019. This toolkit is intended to be used widely, including by front-line NHS Healthcare professionals and those involved in local and national planning and policy.
Please see the Mental Health Page for more information on Perinatal Mental Health in including NHS Somerset’s guide to preferred antidepressants while pregnant and lactating as well as further resources for healthcare professionals and parents.
Preconception advice for women with serious mental illness
Guide for healthcare professionals involved in the care of women with serious mental illness (SMI) in primary and secondary care, developed by King’s College London in partnership with Public Health England, NHS England and Tommy’s.
Perinatal Mental Health Treatment provides free evidence-based resources for new parents and clinicians.
Healthier Together provides maternal mental health patient information and resources.
Specialist Pharmacy Service – Depression: treatment during pregnancy
Also see the Mental Health Page for further links.
Nausea and vomiting of pregnancy is very common. It is characterised by nausea and vomiting and while it can be worst in the first trimester (12 weeks), most cases resolve by 16-20 weeks however some may suffer from it throughout their pregnancy.
By the time people seek advice from healthcare professionals about nausea and vomiting in pregnancy, they may have already tried several different interventions including ginger for mild to moderate symptoms (ginger is not suitable for severe nausea or vomiting of pregnancy).
A few people experience a severe version of pregnancy sickness called Hyperemesis Gravidarum and may require hospital treatment. For patients experiencing moderate-to-severe nausea and vomiting, they may require fluids. Acupressure may be used as an adjunct treatment. Inpatient care may be required if vomiting is severe and not responding to primary care or outpatient management.
Pregnancy sickness support is a useful resource for support and advice on pregnancy sickness.
Severe Vomiting in Pregnancy - NHS Patient website
Nausea & vomiting from BUMPS Best use of medicines in pregnancy (BUMPS) from UK Teratology Information Service (UKTIS)
UKTIS statement on the use of ondansetron in the first 12 weeks of pregnancy, in Somerset it remains second line where first line treatments have failed, provided discussion is had with the parent over risks and benefits. Use the statement to share numbers for patients to make an informed decision
Vomiting in pregnancy whilst still breastfeeding – Breastfeeding and Medication and Hyperemesis and breastfeeding have been shared by Dr Wendy Jones MBE
February RCOG update coming soon. 22/04/2024
RCOG GTG 69 RCOG guideline link and PDF: RCOG guidelines to the management of nausea and vomiting of pregnancy and Hyperemesis Gravidarum GTG69 PDF. SPS has also developed a Q&A on nausea and vomiting in pregnancy.
NICE NG201 Recommendations: Antenatal care has summarised the advantages and disadvantages of different pharmacological treatments for nausea and vomiting in pregnancy NG201 Table 1 Advantages and disadvantages of different pharmacological treatments for nausea and vomiting in pregnancy
Drugs available for treating nausea and vomiting in pregnancy taken from NICE and RCOG guidance
See Appendix III of RCOG Green-top Guideline No. 69 for recommended antiemetic dosages for nausea and vomiting of pregnancy.
First line options:
| Drug | Licensed indications | Doses for licensed indications | Is this licensed for nausea and vomiting in pregnancy? |
| Doxylamine/pyridoxine (combination drug- brand Xonvea®) |
Nausea and vomiting of pregnancy |
Orally: starting dose of TWO tablets at bedtime on day 1. If symptoms persist, the dose can increase to TWO tablets at bedtime on day 2, increasing to ONE tablet in the morning and TWO tablets at bedtime on day 3 if necessary. The dose can increase to a maximum of ONE tablet in the morning, ONE tablet at lunchtime and TWO tablets at bedtime from day 4. Treatment should continue with regular dosing, not for when required use. If stopping, the dose should be gradually reduced to avoid rebound symptoms. Regular review recommended. |
Yes. |
| Promethazine hydrochloride | Nausea and vomiting | Orally: 12.5 – 25mg up to 4 times day | No, but established practice and used for many years. BUMPS – best use of medicine in pregnancy |
| Cyclizine | Nausea and vomiting | Orally: 50mg up to 3 times a day | No, but established practice and used for many years. BUMPS – best use of medicine in pregnancy |
| Prochlorperazine | Severe nausea and vomiting | Oral tablets: 5-10mg given 2-3 times a day, max 30mg/day Buccal tablets: 3-6mg twice a day. |
No, but established practice and used for many years. BUMPS – best use of medicine in pregnancy |
Second line options:
| Drug | Licensed indications | Doses for licensed indications | Is this licensed for nausea and vomiting in pregnancy? |
| Metoclopramide | Nausea and vomiting | Maximum duration of treatment: 5 days. Dose in adults >18 years of age and >60kg body weight: Orally: 10mg up to 3 times a day |
No, but established practice as second-line treatment for nausea and vomiting in pregnancy. BUMPS – best use of medicine in pregnancy |
| Domperidone | Nausea and vomiting | Maximum duration of treatment: one week. Doses for adults and adolescents ≥35kg: Orally 10mg given 3 times a day, maximum 30mg/day |
No, domperidone should only be used during pregnancy when justified by the anticipated therapeutic benefit. Domperidone 10mg Tablets – Summary of Product Characteristics |
| Ondansetron | Nausea and vomiting associated with chemotherapy, radiotherapy and post-operative |
Orally: up to 4-8mg twice a day RCOG guidance for use The Management of Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum ondansetron orally: 4–8 mg 6–8 hourly |
No, but established practice as treatment for severe nausea and vomiting in pregnancy. BUMPS – best use of medicine in pregnancy Small increased chance of cleft lip or cleft palate when taken in the first 12 weeks. This is an increase of 3 extra cases per 10,000 from a background prevalence of 11 in 10,000 to 14 in 10,000. Use in the First trimester if clinically necessary where first line treatments have failed with informed consent from the parent. |
SPS – Pain: treatment during pregnancy the Specialist Pharmacy Service have published signposting evidence based information on the treatment of pain in pregnancy.
Healthcare professionals are reminded systemic NSAIDs are contraindicated during the last trimester of pregnancy, and alerted to new advice that use from week 20 be avoided unless clinically required, due to risk of oligohydramnios and premature closure of the ductus arteriosus. See Non-steroidal anti-inflammatory drugs (NSAIDs): potential risks following prolonged use after 20 weeks of pregnancy from Specialist Pharmacy Service.
See our Thyroid Conditions webpage
Vitamin D supplements should be taken daily for the duration of pregnancy, ideally from 3 months prior to conception if possible.
Vitamin D should then continue for the duration of lactation more information can be found on the Somerset Medicines Management Lactation page.
Advise people planning pregnancy, those who are pregnant and/ or breastfeeding and chestfeeding to take Vitamin D 10 micrograms per day. PH56 Vitamin D: supplement use in specific population groups.
Supplementation of vitamin D is suitable for self-care unless the patient is deficient-
Treatment of deficiency (Vitamin D <25nmol/l) formulary options available on the Somerset Prescribing formulary. An upper daily dose of 4,000iu daily for 10 weeks is preferred while pregnant more information can be found on the Specialist Pharmacy Service website:
Dosing and monitoring for treatment of Vitamin D deficiency in pregnancy
Healthy Start vitamins are available for families who qualify for free, see how to apply. Healthy Start women’s vitamin tablets contain folic acid and vitamins C and D (Children’s drops also available). FAQs. The application form must be signed by a midwife, health visitor, doctor or nurse.
The information and links provided are for guidance, clinical decisions remain the responsibility of the practitioner; the intention is to help prescribers find evidence based information and does not replace input from appropriate professionals or constitute medical advice for individual patients.
