It is fairly easy to determine when conception occurred based on last menstrual period (don’t give them a false date here because it is very important to date your pregnancy accurately) and uterine size from ultrasound, so it may not be prudent to mislead your prenatal care providers about when the pregnancy began.

Many women are faced with the dilemma of becoming pregnant with no medical insurance or switching jobs or plans when they are already pregnant. The following information comes from an organization called Consumer Insurance Guide: Insurance News Network. Their mission is to deliver accurate, unbiased insurance news for consumers. They offer tips, in-depth stories, and expert guidance on auto, homeowners, health, life, and business insurance, plus annuities. They are an independent news site that does not sell insurance and are not owned or operated by an insurance company.

Pregnancy complicates health insurance options. Federal law bars pregnancy from being considered a preexisting condition, which means if you change health plans while you’re pregnant, your new insurer can’t deny claims related to your pregnancy. But a variety of loopholes means pregnant women could still lack insurance coverage for their prenatal care if they don’t do some careful planning.

Under a law known as HIPAA, the Health Insurance Portability and Accountability Act of 1996, health insurers cannot consider pregnancy a preexisting condition. So, unlike illnesses such as diabetes, they can’t deny you coverage when you go from one job to another and switch health plans.

“It was not good public policy to have a pregnant woman with no access to health insurance,” says Kansas Insurance Commissioner Kathleen Sebelius. “We want to encourage prenatal care and regular checkups during the course of a pregnancy and having pregnancy as a preexisting condition would block access to health care.” There are exceptions to the rules, however.

Unfortunately, there are a lot of “buts” to HIPAA. For one thing, HIPAA doesn’t apply to someone who previously had no health coverage at all and then gets into a group health plan through a new job. So if you had no insurance, got pregnant, then landed a new job with insurance, your new health plan would not have to immediately cover your pregnancy. You might have to sit out a preexisting condition waiting period, a period that could be longer than your pregnancy and in the meantime pay for your visits yourself.

Second, HIPAA applies only to group health plans. So if you have individual insurance and are pregnant, then buy group health insurance, you again could be subject to a preexisting condition waiting period. Likewise, if you move from one individual health plan to another individual health plan, you might not get pregnancy coverage at all. You might have to sit out a waiting period, or if you are offered insurance that covers your pregnancy, you might find it’s very expensive.

“HIPAA is really the only protection against pregnancy being treated as a preexisting condition, and there are lots of people to whom HIPAA rules don’t apply,” Sebelius notes. Eligibility waiting periods are possible.

Here’s another scenario. Say you have group health coverage and then switch jobs. Your new health plan has a one month eligibility period before it begins and you’re pregnant. What can you do? “Probably nothing,” Sebelius warns. The health plan isn’t required to cover your pregnancy until the plan takes effect. While that might not be a problem if you’re early in your pregnancy and you don’t mind paying for a prenatal visit or two out of your own pocket, it could be trouble if you’re in your eighth or ninth month and have no coverage.