If the ectopic pregnancy is diagnosed on its earliest stages, it is possible to be treated with the help of some medications. As a rule a drug, called methotrexate is applied in these cases. This medicine works by killing any rapidly dividing cells, that is why methotrexate was originally designed to be applied in chemotherapy, as it also concerns cancer cells. However, injections of methotrexate, though given in much lower doses, rather than those, given in chemotherapy have proved to be quite effective in ectopic pregnancy treating in more than 90 percent of all cases.

Most generally methotrexate is given as a single injection into a muscle. The dose, every woman is to receive is calculated taking into consideration her height and weight. Four days after the injection of methoterxate was given to a woman, she is to conduct a blood test in order to measure the level of the hormone hCG, and then it is necessary to make one more blood test three more days later. During this time the hCG level is to decline at least 15 percent between the fourth and the seventh days in order for the single injection would be considered to be successful. If the decline of the level of hCG hormone is adequate, weekly hCG levels are followed along with the clinical status of a woman, until it is determined that the ectopic pregnancy is resolved. In case if the general health condition of a woman becomes unstable somewhere during these days, she is to be rushed to the hospital for surgical intervention. Therefore, in case if it reveals that the decline of the hCG hormone is not adequate, the woman is reassessed in order to determine whether a second injection of methotrexate would be appropriate to make. 

In order to make the medical therapy as effective as possible, the woman is to fit several strict enough criteria, such as:
1. a woman is to have an ectopic pregnancy on its earliest terms, when her tube has not get ruptured yet;
2. a woman is to have very few or no symptoms of ectopic pregnancy at all;
3. a woman is to have good heart function as well as stable blood pressure;
4. a woman is to be reliable, as she has to agree to call her doctor right away in case if any problem occurs, and she is to be willing to come back for testing and clinical follow – up;
5. a woman is to have good general health condition. Her blood counts, as well as the function of her kidneys and liver are to be normal before she starts taking methotrexate.

Medical therapy has several advantages over the surgical intervention, such as:
1. Medical therapy is considered to be less invasive. It comes out from the very definition of the word “surgery” – it is invasive, or in other words, it involves the cutting of tissue and the opening of body cavities. Thus, it can potentially become the reason of some damage of the fallopian tube, which can result in lower subsequent pregnancy rates as well as in higher repeat ectopic pregnancy rates.
2. Medical therapy is considered to be less expensive. There is no doubt, that the total cost for treating and monitoring an ectopic pregnancy, including all medications, is much more lower than that of general anesthesia and surgery.
Still, there exists one disadvantage of medical therapy over the surgery – it is the longer time frame, necessary to resolve the health condition of a woman, in comparison with the immediate surgical termination of ectopic pregnancy.