They have to consider the likelihood of seizures, whether their medication poses any risk to their baby and the potential risk of birth defects.
"I recently had an unexpected seizure and have been in hospital for the past few days being monitored," Cosima Pole, 39, who has epilepsy and is eight months pregnant with her third child told The Huffington Post UK.
"I've struggled with baby brain really badly this pregnancy and forgot to take my medication. I was with my husband who called 999.
"The paramedics took me to the delivery ward. The baby is fine - it's just very scary."
Every year around 2,500 women with epilepsy in the UK have a baby, according to the Epilepsy Society.
For some, they will enjoy a pregnancy and birth with unchanged seizure frequency and more than a 90% chance of having a healthy baby.
But for others, pregnancy can be an incredibly challenging time.
"A woman with epilepsy may be so fearful of risks and complications for her and baby that her anxiety and stress levels induce tocophobia [fear of pregnancy and childbirth]," epilepsy midwife Kim Morley, founder of Women With Epilepsy, told HuffPost UK.
"Women with epilepsy are at increased risk of depression and anxiety therefore there should always be a holistic, sensitive approach to care in labour, even if their condition is extremely unstable."
Pole was diagnosed with epilepsy when she was 16 years old. She discussed pregnancy with her neurologist as she was concerned about the risks associated with being on medication while carrying a baby.
"My fear was the dilemma of what is worse for your baby - being off medication and having seizures, which can cut off the blood supply to the baby, or exposing the baby to the drugs," she said.
"The decision was taken away from me thankfully, as I can not come off my medication."
Epilepsy Society's medical director Professor Ley Sander said most women do not find that their seizures change during pregnancy, but for some, their medication levels may need to change dramatically.
"Their epilepsy medication should be discussed with a GP or epilepsy specialist and adjustments made, where necessary, to dosage or the time at which the medication is taken," he said.
When she fell pregnant, Pole turned to the UK Epilepsy and Pregnancy Register to talk to a specialist epilepsy midwife. But even with support, she said the biggest struggle she constantly faced throughout pregnancy was "fear".
"During my first pregnancy I was very scared that labour would make me have a seizure as it involves all of my triggers - stress, lack of sleep, worry, nerves, fear, anxiety, hormones," she explained.
"Pregnancy is a fairly scary thing as it is, particularly your first when you are entering into the great unknown, but add in uncontrolled epilepsy and the increased risk of foetal abnormality and it makes it a very difficult and emotional time."
Pole described her first labour as being "very painful and stressful". She had an epidural and her daughter needed to be resuscitated when she was born.
"The hospital midwives didn't know me or my situation," she said. "It made me scared.
"My second birth was worse," she added. "I had wanted an early epidural and had been given the OK for this, but the midwives would only offer me Pethidine [pain relief], which I didn’t want as I had read of a link to seizures.
"The induction wouldn’t work and I was exhausted and very emotional. My baby’s heart rate kept on dropping, so I was stuck on a bed being monitored and getting more and more scared.
"With my third, my epilepsy is not something I’m even thinking about this time - I’m focusing on a calm birth over avoiding a seizure."
Clair Cobbold, who is mum to Riley, three, and Benji, six months, has temporal lobe epilepsy.
She said she felt incredibly lonely during her first pregnancy, which wasn't helped by the added fear of what else could go wrong.
"You have all the normal concerns about being a mum and how it can change your life, but you also are given information about epilepsy, pregnancy and birth defects," Cobbold told HuffPost UK.
"It's quite scary and at my 12-week scan I was so scared that something was going to be wrong with the baby because of all the information I had read."
"Throughout my pregnancy I just did everything my doctors told me - I was being seen by a London epilepsy team, who would write to my local team, but my local team didn't know much about epilepsy at all," Cobbold explained.
"I think I just didn't have much confidence with any of it."
During Riley's birth, Cobbold was given an anti-epileptic drug, but unfortunately this caused her labour to slow down.
"It ended up being a very traumatic birth because it was slowed down by the drug," she added.
"I had to have a forceps delivery and suffered with PTSD after."
Cobbold found support through the Epilepsy Society after the birth of her first child and it was then she met midwife Kim Morley.
However by this point, Cobbold said she had already decided to go down the route of adoption, as she felt she couldn't handle going through pregnancy and birth again.
"Kim told me pregnancy didn't need to be medicalised, especially if your epilepsy is well-controlled and when I explained the medications I had been given she told me they slowed down labour," Cobbold said.
Cobbold was told if she were to fall pregnant again, she should call on the support of an epilepsy midwife who would be more knowledgable about her condition and support her concerns.
"I did fall pregnant again and for my second birth, I saw Kim and felt much more relaxed, with a chance to enjoy my pregnancy," Cobbold said.
"If I had been sick, I would call and ask her what to do and having that support was useful. With epilepsy you just need someone who knows the answer, it gives you confidence."
Morley said her main concern for pregnant women who have epilepsy is that many feel "disempowered" during the nine months.
"I do everything I can to pass on my knowledge to empower women to become experts in managing their own condition," she explained.
"To reduce fears that surround epilepsy, it's important for women to learn more about their health condition.
"Epilepsy support groups have a wealth of support devices to enable women to understand what epilepsy is, how their treatment works and support mechanisms and opportunities.
"This includes medication aids, as forgotten tablets are one of the leading causes of seizure recurrence."
Morley also suggested women should ask their midwife or epilepsy specialist to improve their self management by working together to form a plan for how they would like their pregnancy/birth to go, as well as how to manage risks.
"Putting the woman in charge of this plan takes away the risks associated with delay accessing professional advice," she said.
"Encouraging the woman to share the knowledge of her epilepsy and management of seizures with family and friends helps her wider support network in the event she were to experience a seizure."
Since giving birth to her second child, Cobbold said speaking to other mums who have epilepsy has been a huge support for her.
"Women need to know there is support out there and they just need to have the confidence to talk to them about it," she added.
"Epilepsy Society’s website and message boards have been a constant source of information and support throughout."