My OH is a Dr and as I am at high risk of developing pre-eclampsia in this pregnancy,he has being doing some research and decided that we should be following an evidence based medical practice after finding this study:
Dutch researchers conducted a series of studies that confirmed a surprisingly strong correlation between a diminished incidence of pre-eclampsia and a woman's practice of oral sex, and noted that the protective effects were strongest if she swallowed her partner's semen.[55][56][57][58][59][60] The researchers concluded that while any exposure to a partner's semen during sexual activity appears to decrease a woman's chances for the various immunological disorders that can occur during pregnancy, immunological tolerance could be most quickly established through oral introduction and gastrointestinal absorption of semen.[56][57]
Funnily enough my consultant didn't mention this particular study....
The link if anyone is interested in the full article here