If a father’s Rh factor genes are + +, and the mother’s are – -, the baby will have one + from the father and one – gene from the mother. If a father’s Rh factor genes are + +, and the mother’s are + +, the baby will have one + from the father and one + gene from the mother. More specifically, consider the following: If a person has the genes – -, the Rh factor will be negative.Ī baby receives one gene from the father and one from the mother.

If a person has the genes + -, the Rh factor will also be positive. If a person has the genes + +, the Rh factor in the blood will be positive. The Rh-positive gene is dominant (stronger) and, even when paired with an Rh-negative gene, the positive gene takes over: Rh factors follow a common pattern of genetic inheritance. A baby may have the blood type and Rh factor of either parent or a combination of both parents. The following are the possible combinations of blood types with the Rh factors: If there is no Rh factor protein, the person is Rh- negative. If the Rh factor protein is on the cells, the person is Rh-positive. The Rh factor is a protein that is found on the covering of the red blood cells. The blood type is found as proteins on red blood cells and in body fluids. The blood type and the Rh factor simply mean that a person’s blood has certain specific features. Patient Financial Responsibility Policyīlood Types in Pregnancy About blood typesĮvery person has a blood type (O, A, B, or AB) and an Rh factor, either positive or negative.

Pregnancy with o negative blood type