Does It Matter if Baby’s Bottle has Formula vs. Breastmilk?

Question

Hi, my name is Katie. I have a seven month old baby and I have read many responses to the “return to fertility while nursing” questions. When you say “supplement with a bottle” does that mean formula or expressed milk? If my baby is mostly breastfed except for two feedings a day occasionally- and that milk is pumped- does it affect my fertility? He only does a little jar of baby food per day, and the rest is breast milk- pumped or otherwise. Also, I’ve heard that the mucous method is not as reliable when nursing because of hormonal stuff- are there specific signs I can watch for while I am breastfeeding?
Thanks

Answer

Last Updated: February 6, 2022
Dear Katie,

When feedings at the breast are supplemented with bottle feedings (regardless of what is in the bottle) and / or solids, the woman is no longer feeding the baby totally at the breast. I think you are seeking clarification in this definition because of information on our website which explains if a woman is totally breastfeeding (not supplementing with bottles or baby food) then she will be infertile for the first eight weeks following the baby’s birth. But your baby is seven months old, so that is a moot point.

How soon fertility returns varies, dramatically. But the Ovulation Method is absolutely reliable in identifying the return of fertility, whenever it occurs.

So feed your baby in the way that is best for you and your baby, and learn NFP from a certified teacher to identify the return of fertility, and reliably know on any given day if you are fertile or infertile.

Sheila St. John

Answered By:

Sheila St. John
Sheila St. John is the Executive Director of the California Association of Natural Family Planning, coordinating the non-profit’s education and advocacy efforts throughout the state. Initially attracted to NFP as a healthy, effective method for planning families, drug, device and surgery free, her passion for NFP has grown over the last 42 years as she has journeyed with the over 900 couples she has personally instructed in its use, and been privileged to witness its role in overcoming infertility, women’s health, and the transformation that occurs in lives of men, women, and families, when we embrace God’s design for love and life.

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