While in utero, babies receive oxygen, blood, and nutrients through the placenta. Many substances that a woman ingests, including medications, can cross the placenta and potentially affect the fetus. As such, a lot of women avoid taking anything that could potentially affect the health and safety of their baby, including medications and drugs.
After developing a bacterial infection of some kind, many pregnant women wonder whether it is safe for them to take antibiotics or whether they would be better off riding it out.
When it comes to antibiotics and pregnancy, the good news is that some are considered safe – but others should be avoided due to the potential risk they pose for an unborn baby. Here, we’ve taken a closer look at what is ‘safe’ and what is not.
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Can You Take Antibiotics When Pregnant?
Yes, but only certain ones, and only when prescribed by your doctor.
Some antibiotics are safe to use during pregnancy, such as penicillins and cephalosporins, while others should be avoided as they can harm your baby’s development.
Reasons to Take Antibiotics During Pregnancy
Certain infections, if left untreated, may be dangerous to the health of a pregnant woman and her unborn baby. They may also pose a higher risk for miscarriage, preterm labour, stillbirth, newborn death, and/or problems with the baby’s organs.
Some of the common reasons that a pregnant woman is given antibiotics include:
- Positive Group B Streptococcus (GBS) Swab
In the lead-up to your due date, your gynaecologist will swab you for GBS. This bacterium can be found in the body and easily passed onto a baby during birth. It has the potential to cause meningitis, pneumonia, or sepsis. If you test positive for or are suspected to have GBS, you will be given an IV antibiotic (usually penicillin) during labour. - Premature Water Breakage
If a woman’s water breaks before her pregnancy has reached full term (especially before 34 weeks gestation), she may be treated with antibiotics to help prevent any infections from reaching the baby before it’s delivered.
Other reasons that a doctor may prescribe antibiotics, even during pregnancy, include a urinary tract infection (UTI), gallbladder infection, placenta and amniotic fluid infection, kidney infection, bacterial vaginosis, listeria, and syphilis.
What Antibiotics Are ‘Safe’ in Pregnancy?
While no medication is completely without risks, antibiotics generally considered safe to take during pregnancy include:
- Penicillin (such as amoxicillin)
- Macrolides (such as erythromycin)
- Cephalosporins (such as cephalexin)
- Metronidazole (an antibiotic used to treat certain vaginal infection such as bacterial vaginosis)
Some antibiotics may need to be prescribed even though there are safety concerns for using them during pregnancy. These include nitrofurantoin, trimethoprim, and sulfamethoxazole. These antibiotics are commonly used to treat UTIs, which are common during pregnancy and may cause complications if left untreated.
What Antibiotics Are Unsafe in Pregnancy?
Some antibiotics are avoided altogether during pregnancy due to the risks they pose to the unborn baby. These unsafe antibiotics in pregnancy include:
- Tetracycline (such as minocycline, oxytetracycline, and doxycycline), typically used to address acne and respiratory infections
- Streptomycin, used for tuberculosis
- Ciprofloxacin, used to manage UTIs
These antibiotics have been associated with fetal side effects, such as discoloured teeth, hearing loss, or abnormal bone development, based on human and animal studies.
Can Pregnant Women Take Ampicillin?
Ampicillin is generally considered one of the safer antibiotic options during pregnancy. It belongs to the penicillin family and has been widely used for decades to treat bacterial infections in pregnant women across Australia and worldwide.
The TGA classifies ampicillin as Pregnancy Category A, meaning it has been taken by a large number of pregnant women without any proven increase in the risk of harm to the baby – making it one of the more trusted antibiotics in obstetric care.
Australian doctors commonly prescribe it during pregnancy for:
- Urinary tract infections (UTIs), which are particularly common in pregnancy
- Group B Streptococcus (GBS) — often given intravenously during labour
- Respiratory and other bacterial infections
It is generally considered safe across all trimesters, though it should always be prescribed and monitored by your GP, obstetrician, or midwife.
When Are Antibiotics Not Needed During Pregnancy?
Antibiotics only work against bacterial infections — they won’t help with colds, flu, or most coughs and sore throats, which are caused by viruses. If your symptoms are mild and viral, your doctor will likely recommend rest, fluids, and safe pain relief instead. Always check with your GP before assuming you need antibiotics.
Taking Antibiotics Safely in Pregnancy
You should always follow your doctor’s instructions when taking antibiotics, particularly during pregnancy.
Your gynaecologist will consider a range of factors before prescribing antibiotics to ensure that they’re necessary for your gestation and pose minimal risk to you and your unborn child. Most gynaecologists will:
- Use extra caution when prescribing antibiotics in the first trimester but will proceed if the benefits outweigh the risks.
- Confirm the type of injections with appropriate tests.
- Prescribe the lowest effective dose.
- Prescribe antibiotics for the shortest necessary duration.
- Use only one type of antibiotic
- Only prescribe antibiotics when absolutely necessary
Pregnant women with a minor infection that doesn’t require antibiotics should consult their doctor about safe over-the-counter alternatives.
Can Antibiotics Cause Miscarriage in Early Pregnancy?
This is a common concern, and the evidence is mixed. Most antibiotics that are routinely prescribed during pregnancy, such as penicillins – are not associated with an increased risk of miscarriage.
However, some studies have suggested a possible link between certain antibiotics, such as erythromycin and nitroimidazoles, and a slightly higher risk in early pregnancy.
Your doctor will only prescribe an antibiotic during the first trimester if it is genuinely necessary and considered safe.
Antibiotics and Pregnancy: The Takeaway
So, are antibiotics safe during pregnancy? The answer is that it really depends on the specifics of the situation.
In many cases, the risk of a child being exposed to an untreated infection is higher than the risk of being exposed to antibiotics. It’s important to speak to your doctor about any concerns so that you can work together to keep both you and your baby safe.
The obstetricians and gynaecologists at Create Health are committed to equipping patients with all the information needed to make informed decisions about their health. If you are pregnant and suspect that you need antibiotics, book an appointment with us today to discuss all your options.
Sources
- TGA Prescribing Medicines in Pregnancy Database https://www.tga.gov.au/resources/health-professional-information-and-resources/australian-categorisation-system-prescribing-medicines-pregnancy/prescribing-medicines-pregnancy-database
- TGA Australian Categorisation System for Prescribing Medicines in Pregnancy https://www.tga.gov.au/resources/health-professional-information-and-resources/australian-categorisation-system-prescribing-medicines-pregnancy
- Safer Care Victoria — GBS Screening and Management Guidelines https://www.safercare.vic.gov.au/best-practice-improvement/clinical-guidance/maternity/group-b-streptococcus-gbs-screening-and-management
- Drugs.com — Ampicillin Use During Pregnancy (TGA & FDA classifications) https://www.drugs.com/pregnancy/ampicillin.html
- CMAJ Study — Antibiotics During Pregnancy and Risk of Spontaneous Abortion (Muanda et al., 2017) https://pmc.ncbi.nlm.nih.gov/articles/PMC5415390/
- NPS MedicineWise — Amoxicillin in Pregnancy https://www.nps.org.au/medicine-finder/amoxycillin-generichealth-capsules
- Australian Prescriber — Drug Safety in Pregnancy https://australianprescriber.tg.org.au/articles/drug-safety-in-pregnancy.html