The report, The Role of GPs in Maternity Care - What Does the Future Hold, will feed into a King's Fund inquiry into the quality of general practice.
GPs should take a more active role in delivering maternity care by sharing responsibilities with midwives and obstetricians, the report says.
Because GPs hold information on patients' medical history and their social context, they could be better placed to pick up problems early, it adds.
Shared care between GPs, midwives and obstetricians could result in better coordination of support for women with complicated medical histories, the report says.
But it also warns this could confuse pregnant women about who is in charge of their care and who to turn to if they are unwell. It also says the current lack of training for GPs would have to be addressed.
GPs should look at pre-conception care and the care of pregnant women as part of their continuing professional development, the report says. They should also establish relationships with maternity services to agree protocols for referral and sharing information.
Anna Dixon, lead author and director of policy at the King's Fund, said: 'It is right that those with specialist skills, such as midwives and obstetricians, take the lead role in caring for pregnant women, but GPs have a vital role to play in pre-conception and shared antenatal and postnatal care.'