Can my employer refuse to let me return to work after being released by my doctor to return after 7 months of leave for pregnancy complications?

There is actually a case decided by the West Virginia Supreme Court of Appeals on this point.  In Haynes v. Rhone-Poulenc, the WVSCA held that complications resulting from pregnancy constitute a disability under W.Va. law, and that an employer must offer the employee "reasonable accommodation" for that disability, including but not limited to modification of leave policies to allow the employee to return to work after the medical leave.  In such cases the fact the condition is pregnancy related usually means the employer should have a reasonably good idea when the employee will return to work, and therefore may be required to hold the position - or an equivalent position - open pending the woman's return.  Whether or not that applies in your case, however, would depend on the specific facts of your case such as 1) whether the employer had to fill the position our of "business necessity," 2) whether the employer could have continue to hold the position open by using a temporary employee, etc. 3) whether your doctor had provided the employer with a specific date upon which the physician anticipated you would be cleared to return, and 4) whether the employer had an available position at the time you were released to return.