The Duke and Duchess of Cambridge announced that Kate Middleton is pregnant again. This is only 13 months after she gave birth to Prince George. Some people took notice of and began to ask about the risks of short pregnancy spacing.

According to research, having an interval of 18 to 23 months between the birth of one child and conception of the next works best for both mother and child. Risks come with short pregnancy spacing. According to Mayo Clinic, these include increased risk of:

• "Autism in second-born child
• The placenta partly or completely peeling away from the inner wall of the uterus before delivery, and
• The placenta attaching to the lower part of the uterine wall, partially or totally covering the cervix - in women who had a first birth by caesarian section"

Women, who also try to do vaginal birth less than 18 months after previous caesarian delivery, are also at risk of uterine rupture. Getting pregnant within 18 months from previous delivery may increase risk of low birth weight, pre-term birth, and small size for gestational age.

With Kate Middleton getting pregnant again - clearly a case of short pregnancy spacing, experts believe that mothers are not given sufficient time to improve on physical stress. Many women are not aware that when expecting and breastfeeding, reduction of stored essential nutrients (like iron and folate) happens. Only after these stages that they have the time to replace those lost stored nutrients. However, becoming pregnant prevents them from doing so. This may then affect the health of the baby and the mother.

There are exceptions to the 'rule', however. According to the report of Yahoo! News, short pregnancy spacing should not be an issue "if a woman is in very good health, takes prenatal vitamins and has access to good prenatal care - as Kate Middleton does". "She should do fine," said Dr. Jill Maura Rabin, co-chief, Division of Ambulatory Care, Women's Health Programs at the North Shore-LIJ Health System.