Barely. There is no solid evidence that position affects conception: the sperm capable of fertilizing enter the cervical canal within seconds of ejaculation. Positions with deeper penetration may deposit sperm a little closer to the cervix, but the difference is tiny.
The reason positions barely matter is speed. The sperm that can actually fertilize the egg reach the cervical canal within seconds of ejaculation. From there, fertile cervical mucus does the work: it keeps sperm alive for up to 5 days and guides them toward the uterus. By the time you change position, the sperm that count are already on their way.
Positions with deeper penetration, such as missionary, may deposit sperm closer to the cervix. The book's verdict is that the difference is tiny.
"You have to lie upside down afterward." There's no scientific evidence of any benefit. Positions, hip elevation, "doing a handstand": none of that changes the conception rate, according to studies published in Fertility and Sterility.
| Practice | What the book says |
|---|---|
| Elevating your hips for 30 minutes | No scientific backing, but it does no harm |
| Pillows or hip elevators after sex | Don't change conception rates in controlled studies |
| Handstand or lying with your legs up | Doesn't change conception rates in controlled studies |
| Strenuous exercise immediately after sex | Better avoided: sperm may have a better shot if you stay put |
So if lying still for a while after sex puts your mind at ease, go ahead: it costs nothing and does no harm. Just don't spend money on special pillows or hip elevators: the book lists them among the products with no evidence.
The book is clear on what matters far more than position: having sex at the right moment, with adequate sperm quality, in a receptive endometrium.
Positions and post-sex rituals don't change the conception rate. The energy you would spend on them is better spent on these three.
Positions are covered in Chapter 26 of Map to the Positive, "Sex at the right time", in Station III (Optimization), with the myths about rituals in Chapters 3 and 27. Chapter 26 also gives the optimal intercourse strategy with a day-by-day example, the lubricants that harm sperm and how to keep sex from turning into a task over months of trying.
Take 30 days. If it does not give you more clarity than everything you have read for free so far, ask for a refund and you get every cent back. We cannot promise you a pregnancy. We can promise you will not be guessing.