myself havent had issue with pregnancy now for few years, before was pain when you had at start 5% chance of impregnation on ovul day, and then it started to climb 10%/... up to now that you got chance at any day outside of ovul week.
its simple always have sex on exact ovul day, 2 days after can be included any more is no longer 100% unless you meet special conditions. learn to use console is simple,
every time you have sex use NamOvul = current day,
when you see seed animations (there are 3 up to penetration of egg) let animation run its course till you click forward.
if for what ever reason you dont see 3rd animation,
next time use dif scene, each girl got at least 2 sex scenes, and extend them to max (those 2, 3 seeds pics beside text), always choose option that allow you to extend sex scene and pump more seed.
that recipe works for em every time, havent had issue with knocking them up in ages, tho then again i dont restart game every time and i know that at least 1st sometimes 2nd not sure 3rd kids are scripted.