Vile vijiti vinakuwa na life span, eg three yrs, 5 yrs etc. Unapoweka kinakuwa kina induce some chemical ambazo huzuia mimba.
In that case, akiweka kijiti akapata mimba it's either.
1. Kime expire i.e beyond it's life span
2. Walimuweka vibaya.
NB. Anaweza akawa na dalili za mimba but akawa hana ila ni reaction ya hicho kijiti na hormones za mwili AU.
Ana mimba, lakini kutoka na hormones inbalance or hormonal complexion HGC hormones zimechelewa kurise.
Mimba haijifichi, time tells all.