Official figures show that just 42.8% of mothers-to-be have come forward for the seasonal vaccination scheme, despite the risk of serious complications for those who catch flu.
The vaccine can also help protect babies for up to three months after their birth, but the statistics from Health Protection Scotland suggest uptake of the jab has actually fallen in the past year.
Scotland striker Suzanne Grant was vaccinated before giving birth to son Oscar, who is now three weeks old, and said it important for mothers-to-be not to put themselves at risk of falling ill after catching the virus.
The 29-year-old, who pays for the Celtic and Scotland women's teams, said: "My midwife had explained the benefits of getting the flu vaccination to me but my aunt who is also a midwife recommended getting immunised as it also protects my baby for up to three months after birth.
"Getting the jab is easy and it's good for me and my baby, so now we're both protected this winter."
Grant, from East Kilbride, added: "I'll be back at training in a couple of weeks in the New Year, so the last thing I want is to be struck down by flu when I'm just getting back into my football.
"I'd urge anyone who is pregnant to get vaccinated - it's not worth the risk of becoming ill with flu."
Mothers-to-be run the risk of major complications if they are struck down by flu because the immune system changes during pregnancy.
Doctors say the flu vaccine is safe for pregnant women and point to evidence which shows the vaccine can also help protect baby for the first three months after birth.
Gillian Smith, of the Royal College of Midwives, said: "We would encourage midwives and pregnant women to get vaccinated to protect themselves.
"Women should be aware of the importance of having the seasonal flu vaccination as soon as they become pregnant. If any pregnant woman is unsure about this, I would urge them to speak to their midwife or doctor."
Earlier this month it emerged that only 45% of two and three-year-olds in Scotland have received the winter flu jab as part of an extension of the vaccination programme.